diff --git a/cmd/serve.go b/cmd/serve.go
index 9fcf550c..62e0a14a 100644
--- a/cmd/serve.go
+++ b/cmd/serve.go
@@ -6,23 +6,22 @@ import (
 	"errors"
 	"fmt"
 	"github.com/stripe/stripe-go/v74"
+	"github.com/urfave/cli/v2"
+	"github.com/urfave/cli/v2/altsrc"
+	"heckel.io/ntfy/v2/log"
+	"heckel.io/ntfy/v2/server"
 	"heckel.io/ntfy/v2/user"
+	"heckel.io/ntfy/v2/util"
 	"io/fs"
 	"math"
 	"net"
 	"net/netip"
+	"net/url"
 	"os"
 	"os/signal"
 	"strings"
 	"syscall"
 	"time"
-
-	"heckel.io/ntfy/v2/log"
-
-	"github.com/urfave/cli/v2"
-	"github.com/urfave/cli/v2/altsrc"
-	"heckel.io/ntfy/v2/server"
-	"heckel.io/ntfy/v2/util"
 )
 
 func init() {
@@ -35,7 +34,7 @@ const (
 
 var flagsServe = append(
 	append([]cli.Flag{}, flagsDefault...),
-	&cli.StringFlag{Name: "config", Aliases: []string{"c"}, EnvVars: []string{"NTFY_CONFIG_FILE"}, Value: defaultServerConfigFile, DefaultText: defaultServerConfigFile, Usage: "config file"},
+	&cli.StringFlag{Name: "config", Aliases: []string{"c"}, EnvVars: []string{"NTFY_CONFIG_FILE"}, Value: defaultServerConfigFile, Usage: "config file"},
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "base-url", Aliases: []string{"base_url", "B"}, EnvVars: []string{"NTFY_BASE_URL"}, Usage: "externally visible base URL for this host (e.g. https://ntfy.sh)"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "listen-http", Aliases: []string{"listen_http", "l"}, EnvVars: []string{"NTFY_LISTEN_HTTP"}, Value: server.DefaultListenHTTP, Usage: "ip:port used as HTTP listen address"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "listen-https", Aliases: []string{"listen_https", "L"}, EnvVars: []string{"NTFY_LISTEN_HTTPS"}, Usage: "ip:port used as HTTPS listen address"}),
@@ -45,19 +44,19 @@ var flagsServe = append(
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "cert-file", Aliases: []string{"cert_file", "E"}, EnvVars: []string{"NTFY_CERT_FILE"}, Usage: "certificate file, if listen-https is set"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "firebase-key-file", Aliases: []string{"firebase_key_file", "F"}, EnvVars: []string{"NTFY_FIREBASE_KEY_FILE"}, Usage: "Firebase credentials file; if set additionally publish to FCM topic"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "cache-file", Aliases: []string{"cache_file", "C"}, EnvVars: []string{"NTFY_CACHE_FILE"}, Usage: "cache file used for message caching"}),
-	altsrc.NewDurationFlag(&cli.DurationFlag{Name: "cache-duration", Aliases: []string{"cache_duration", "b"}, EnvVars: []string{"NTFY_CACHE_DURATION"}, Value: server.DefaultCacheDuration, Usage: "buffer messages for this time to allow `since` requests"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "cache-duration", Aliases: []string{"cache_duration", "b"}, EnvVars: []string{"NTFY_CACHE_DURATION"}, Value: util.FormatDuration(server.DefaultCacheDuration), Usage: "buffer messages for this time to allow `since` requests"}),
 	altsrc.NewIntFlag(&cli.IntFlag{Name: "cache-batch-size", Aliases: []string{"cache_batch_size"}, EnvVars: []string{"NTFY_BATCH_SIZE"}, Usage: "max size of messages to batch together when writing to message cache (if zero, writes are synchronous)"}),
-	altsrc.NewDurationFlag(&cli.DurationFlag{Name: "cache-batch-timeout", Aliases: []string{"cache_batch_timeout"}, EnvVars: []string{"NTFY_CACHE_BATCH_TIMEOUT"}, Usage: "timeout for batched async writes to the message cache (if zero, writes are synchronous)"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "cache-batch-timeout", Aliases: []string{"cache_batch_timeout"}, EnvVars: []string{"NTFY_CACHE_BATCH_TIMEOUT"}, Value: util.FormatDuration(server.DefaultCacheBatchTimeout), Usage: "timeout for batched async writes to the message cache (if zero, writes are synchronous)"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "cache-startup-queries", Aliases: []string{"cache_startup_queries"}, EnvVars: []string{"NTFY_CACHE_STARTUP_QUERIES"}, Usage: "queries run when the cache database is initialized"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "auth-file", Aliases: []string{"auth_file", "H"}, EnvVars: []string{"NTFY_AUTH_FILE"}, Usage: "auth database file used for access control"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "auth-startup-queries", Aliases: []string{"auth_startup_queries"}, EnvVars: []string{"NTFY_AUTH_STARTUP_QUERIES"}, Usage: "queries run when the auth database is initialized"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "auth-default-access", Aliases: []string{"auth_default_access", "p"}, EnvVars: []string{"NTFY_AUTH_DEFAULT_ACCESS"}, Value: "read-write", Usage: "default permissions if no matching entries in the auth database are found"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "attachment-cache-dir", Aliases: []string{"attachment_cache_dir"}, EnvVars: []string{"NTFY_ATTACHMENT_CACHE_DIR"}, Usage: "cache directory for attached files"}),
-	altsrc.NewStringFlag(&cli.StringFlag{Name: "attachment-total-size-limit", Aliases: []string{"attachment_total_size_limit", "A"}, EnvVars: []string{"NTFY_ATTACHMENT_TOTAL_SIZE_LIMIT"}, DefaultText: "5G", Usage: "limit of the on-disk attachment cache"}),
-	altsrc.NewStringFlag(&cli.StringFlag{Name: "attachment-file-size-limit", Aliases: []string{"attachment_file_size_limit", "Y"}, EnvVars: []string{"NTFY_ATTACHMENT_FILE_SIZE_LIMIT"}, DefaultText: "15M", Usage: "per-file attachment size limit (e.g. 300k, 2M, 100M)"}),
-	altsrc.NewDurationFlag(&cli.DurationFlag{Name: "attachment-expiry-duration", Aliases: []string{"attachment_expiry_duration", "X"}, EnvVars: []string{"NTFY_ATTACHMENT_EXPIRY_DURATION"}, Value: server.DefaultAttachmentExpiryDuration, DefaultText: "3h", Usage: "duration after which uploaded attachments will be deleted (e.g. 3h, 20h)"}),
-	altsrc.NewDurationFlag(&cli.DurationFlag{Name: "keepalive-interval", Aliases: []string{"keepalive_interval", "k"}, EnvVars: []string{"NTFY_KEEPALIVE_INTERVAL"}, Value: server.DefaultKeepaliveInterval, Usage: "interval of keepalive messages"}),
-	altsrc.NewDurationFlag(&cli.DurationFlag{Name: "manager-interval", Aliases: []string{"manager_interval", "m"}, EnvVars: []string{"NTFY_MANAGER_INTERVAL"}, Value: server.DefaultManagerInterval, Usage: "interval of for message pruning and stats printing"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "attachment-total-size-limit", Aliases: []string{"attachment_total_size_limit", "A"}, EnvVars: []string{"NTFY_ATTACHMENT_TOTAL_SIZE_LIMIT"}, Value: util.FormatSize(server.DefaultAttachmentTotalSizeLimit), Usage: "limit of the on-disk attachment cache"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "attachment-file-size-limit", Aliases: []string{"attachment_file_size_limit", "Y"}, EnvVars: []string{"NTFY_ATTACHMENT_FILE_SIZE_LIMIT"}, Value: util.FormatSize(server.DefaultAttachmentFileSizeLimit), Usage: "per-file attachment size limit (e.g. 300k, 2M, 100M)"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "attachment-expiry-duration", Aliases: []string{"attachment_expiry_duration", "X"}, EnvVars: []string{"NTFY_ATTACHMENT_EXPIRY_DURATION"}, Value: util.FormatDuration(server.DefaultAttachmentExpiryDuration), Usage: "duration after which uploaded attachments will be deleted (e.g. 3h, 20h)"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "keepalive-interval", Aliases: []string{"keepalive_interval", "k"}, EnvVars: []string{"NTFY_KEEPALIVE_INTERVAL"}, Value: util.FormatDuration(server.DefaultKeepaliveInterval), Usage: "interval of keepalive messages"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "manager-interval", Aliases: []string{"manager_interval", "m"}, EnvVars: []string{"NTFY_MANAGER_INTERVAL"}, Value: util.FormatDuration(server.DefaultManagerInterval), Usage: "interval of for message pruning and stats printing"}),
 	altsrc.NewStringSliceFlag(&cli.StringSliceFlag{Name: "disallowed-topics", Aliases: []string{"disallowed_topics"}, EnvVars: []string{"NTFY_DISALLOWED_TOPICS"}, Usage: "topics that are not allowed to be used"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "web-root", Aliases: []string{"web_root"}, EnvVars: []string{"NTFY_WEB_ROOT"}, Value: "/", Usage: "sets root of the web app (e.g. /, or /app), or disables it (disable)"}),
 	altsrc.NewBoolFlag(&cli.BoolFlag{Name: "enable-signup", Aliases: []string{"enable_signup"}, EnvVars: []string{"NTFY_ENABLE_SIGNUP"}, Value: false, Usage: "allows users to sign up via the web app, or API"}),
@@ -76,16 +75,18 @@ var flagsServe = append(
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "twilio-auth-token", Aliases: []string{"twilio_auth_token"}, EnvVars: []string{"NTFY_TWILIO_AUTH_TOKEN"}, Usage: "Twilio auth token"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "twilio-phone-number", Aliases: []string{"twilio_phone_number"}, EnvVars: []string{"NTFY_TWILIO_PHONE_NUMBER"}, Usage: "Twilio number to use for outgoing calls"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "twilio-verify-service", Aliases: []string{"twilio_verify_service"}, EnvVars: []string{"NTFY_TWILIO_VERIFY_SERVICE"}, Usage: "Twilio Verify service ID, used for phone number verification"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "message-size-limit", Aliases: []string{"message_size_limit"}, EnvVars: []string{"NTFY_MESSAGE_SIZE_LIMIT"}, Value: util.FormatSize(server.DefaultMessageSizeLimit), Usage: "size limit for the message (see docs for limitations)"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "message-delay-limit", Aliases: []string{"message_delay_limit"}, EnvVars: []string{"NTFY_MESSAGE_DELAY_LIMIT"}, Value: util.FormatDuration(server.DefaultMessageDelayMax), Usage: "max duration a message can be scheduled into the future"}),
 	altsrc.NewIntFlag(&cli.IntFlag{Name: "global-topic-limit", Aliases: []string{"global_topic_limit", "T"}, EnvVars: []string{"NTFY_GLOBAL_TOPIC_LIMIT"}, Value: server.DefaultTotalTopicLimit, Usage: "total number of topics allowed"}),
 	altsrc.NewIntFlag(&cli.IntFlag{Name: "visitor-subscription-limit", Aliases: []string{"visitor_subscription_limit"}, EnvVars: []string{"NTFY_VISITOR_SUBSCRIPTION_LIMIT"}, Value: server.DefaultVisitorSubscriptionLimit, Usage: "number of subscriptions per visitor"}),
-	altsrc.NewStringFlag(&cli.StringFlag{Name: "visitor-attachment-total-size-limit", Aliases: []string{"visitor_attachment_total_size_limit"}, EnvVars: []string{"NTFY_VISITOR_ATTACHMENT_TOTAL_SIZE_LIMIT"}, Value: "100M", Usage: "total storage limit used for attachments per visitor"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "visitor-attachment-total-size-limit", Aliases: []string{"visitor_attachment_total_size_limit"}, EnvVars: []string{"NTFY_VISITOR_ATTACHMENT_TOTAL_SIZE_LIMIT"}, Value: util.FormatSize(server.DefaultVisitorAttachmentTotalSizeLimit), Usage: "total storage limit used for attachments per visitor"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "visitor-attachment-daily-bandwidth-limit", Aliases: []string{"visitor_attachment_daily_bandwidth_limit"}, EnvVars: []string{"NTFY_VISITOR_ATTACHMENT_DAILY_BANDWIDTH_LIMIT"}, Value: "500M", Usage: "total daily attachment download/upload bandwidth limit per visitor"}),
 	altsrc.NewIntFlag(&cli.IntFlag{Name: "visitor-request-limit-burst", Aliases: []string{"visitor_request_limit_burst"}, EnvVars: []string{"NTFY_VISITOR_REQUEST_LIMIT_BURST"}, Value: server.DefaultVisitorRequestLimitBurst, Usage: "initial limit of requests per visitor"}),
-	altsrc.NewDurationFlag(&cli.DurationFlag{Name: "visitor-request-limit-replenish", Aliases: []string{"visitor_request_limit_replenish"}, EnvVars: []string{"NTFY_VISITOR_REQUEST_LIMIT_REPLENISH"}, Value: server.DefaultVisitorRequestLimitReplenish, Usage: "interval at which burst limit is replenished (one per x)"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "visitor-request-limit-replenish", Aliases: []string{"visitor_request_limit_replenish"}, EnvVars: []string{"NTFY_VISITOR_REQUEST_LIMIT_REPLENISH"}, Value: util.FormatDuration(server.DefaultVisitorRequestLimitReplenish), Usage: "interval at which burst limit is replenished (one per x)"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "visitor-request-limit-exempt-hosts", Aliases: []string{"visitor_request_limit_exempt_hosts"}, EnvVars: []string{"NTFY_VISITOR_REQUEST_LIMIT_EXEMPT_HOSTS"}, Value: "", Usage: "hostnames and/or IP addresses of hosts that will be exempt from the visitor request limit"}),
 	altsrc.NewIntFlag(&cli.IntFlag{Name: "visitor-message-daily-limit", Aliases: []string{"visitor_message_daily_limit"}, EnvVars: []string{"NTFY_VISITOR_MESSAGE_DAILY_LIMIT"}, Value: server.DefaultVisitorMessageDailyLimit, Usage: "max messages per visitor per day, derived from request limit if unset"}),
 	altsrc.NewIntFlag(&cli.IntFlag{Name: "visitor-email-limit-burst", Aliases: []string{"visitor_email_limit_burst"}, EnvVars: []string{"NTFY_VISITOR_EMAIL_LIMIT_BURST"}, Value: server.DefaultVisitorEmailLimitBurst, Usage: "initial limit of e-mails per visitor"}),
-	altsrc.NewDurationFlag(&cli.DurationFlag{Name: "visitor-email-limit-replenish", Aliases: []string{"visitor_email_limit_replenish"}, EnvVars: []string{"NTFY_VISITOR_EMAIL_LIMIT_REPLENISH"}, Value: server.DefaultVisitorEmailLimitReplenish, Usage: "interval at which burst limit is replenished (one per x)"}),
+	altsrc.NewStringFlag(&cli.StringFlag{Name: "visitor-email-limit-replenish", Aliases: []string{"visitor_email_limit_replenish"}, EnvVars: []string{"NTFY_VISITOR_EMAIL_LIMIT_REPLENISH"}, Value: util.FormatDuration(server.DefaultVisitorEmailLimitReplenish), Usage: "interval at which burst limit is replenished (one per x)"}),
 	altsrc.NewBoolFlag(&cli.BoolFlag{Name: "visitor-subscriber-rate-limiting", Aliases: []string{"visitor_subscriber_rate_limiting"}, EnvVars: []string{"NTFY_VISITOR_SUBSCRIBER_RATE_LIMITING"}, Value: false, Usage: "enables subscriber-based rate limiting"}),
 	altsrc.NewBoolFlag(&cli.BoolFlag{Name: "behind-proxy", Aliases: []string{"behind_proxy", "P"}, EnvVars: []string{"NTFY_BEHIND_PROXY"}, Value: false, Usage: "if set, use X-Forwarded-For header to determine visitor IP address (for rate limiting)"}),
 	altsrc.NewStringFlag(&cli.StringFlag{Name: "stripe-secret-key", Aliases: []string{"stripe_secret_key"}, EnvVars: []string{"NTFY_STRIPE_SECRET_KEY"}, Value: "", Usage: "key used for the Stripe API communication, this enables payments"}),
@@ -126,7 +127,7 @@ func execServe(c *cli.Context) error {
 
 	// Read all the options
 	config := c.String("config")
-	baseURL := c.String("base-url")
+	baseURL := strings.TrimSuffix(c.String("base-url"), "/")
 	listenHTTP := c.String("listen-http")
 	listenHTTPS := c.String("listen-https")
 	listenUnix := c.String("listen-unix")
@@ -140,19 +141,19 @@ func execServe(c *cli.Context) error {
 	webPushEmailAddress := c.String("web-push-email-address")
 	webPushStartupQueries := c.String("web-push-startup-queries")
 	cacheFile := c.String("cache-file")
-	cacheDuration := c.Duration("cache-duration")
+	cacheDurationStr := c.String("cache-duration")
 	cacheStartupQueries := c.String("cache-startup-queries")
 	cacheBatchSize := c.Int("cache-batch-size")
-	cacheBatchTimeout := c.Duration("cache-batch-timeout")
+	cacheBatchTimeoutStr := c.String("cache-batch-timeout")
 	authFile := c.String("auth-file")
 	authStartupQueries := c.String("auth-startup-queries")
 	authDefaultAccess := c.String("auth-default-access")
 	attachmentCacheDir := c.String("attachment-cache-dir")
 	attachmentTotalSizeLimitStr := c.String("attachment-total-size-limit")
 	attachmentFileSizeLimitStr := c.String("attachment-file-size-limit")
-	attachmentExpiryDuration := c.Duration("attachment-expiry-duration")
-	keepaliveInterval := c.Duration("keepalive-interval")
-	managerInterval := c.Duration("manager-interval")
+	attachmentExpiryDurationStr := c.String("attachment-expiry-duration")
+	keepaliveIntervalStr := c.String("keepalive-interval")
+	managerIntervalStr := c.String("manager-interval")
 	disallowedTopics := c.StringSlice("disallowed-topics")
 	webRoot := c.String("web-root")
 	enableSignup := c.Bool("enable-signup")
@@ -171,17 +172,19 @@ func execServe(c *cli.Context) error {
 	twilioAuthToken := c.String("twilio-auth-token")
 	twilioPhoneNumber := c.String("twilio-phone-number")
 	twilioVerifyService := c.String("twilio-verify-service")
+	messageSizeLimitStr := c.String("message-size-limit")
+	messageDelayLimitStr := c.String("message-delay-limit")
 	totalTopicLimit := c.Int("global-topic-limit")
 	visitorSubscriptionLimit := c.Int("visitor-subscription-limit")
 	visitorSubscriberRateLimiting := c.Bool("visitor-subscriber-rate-limiting")
 	visitorAttachmentTotalSizeLimitStr := c.String("visitor-attachment-total-size-limit")
 	visitorAttachmentDailyBandwidthLimitStr := c.String("visitor-attachment-daily-bandwidth-limit")
 	visitorRequestLimitBurst := c.Int("visitor-request-limit-burst")
-	visitorRequestLimitReplenish := c.Duration("visitor-request-limit-replenish")
+	visitorRequestLimitReplenishStr := c.String("visitor-request-limit-replenish")
 	visitorRequestLimitExemptHosts := util.SplitNoEmpty(c.String("visitor-request-limit-exempt-hosts"), ",")
 	visitorMessageDailyLimit := c.Int("visitor-message-daily-limit")
 	visitorEmailLimitBurst := c.Int("visitor-email-limit-burst")
-	visitorEmailLimitReplenish := c.Duration("visitor-email-limit-replenish")
+	visitorEmailLimitReplenishStr := c.String("visitor-email-limit-replenish")
 	behindProxy := c.Bool("behind-proxy")
 	stripeSecretKey := c.String("stripe-secret-key")
 	stripeWebhookKey := c.String("stripe-webhook-key")
@@ -190,6 +193,64 @@ func execServe(c *cli.Context) error {
 	enableMetrics := c.Bool("enable-metrics") || metricsListenHTTP != ""
 	profileListenHTTP := c.String("profile-listen-http")
 
+	// Convert durations
+	cacheDuration, err := util.ParseDuration(cacheDurationStr)
+	if err != nil {
+		return fmt.Errorf("invalid cache duration: %s", cacheDurationStr)
+	}
+	cacheBatchTimeout, err := util.ParseDuration(cacheBatchTimeoutStr)
+	if err != nil {
+		return fmt.Errorf("invalid cache batch timeout: %s", cacheBatchTimeoutStr)
+	}
+	attachmentExpiryDuration, err := util.ParseDuration(attachmentExpiryDurationStr)
+	if err != nil {
+		return fmt.Errorf("invalid attachment expiry duration: %s", attachmentExpiryDurationStr)
+	}
+	keepaliveInterval, err := util.ParseDuration(keepaliveIntervalStr)
+	if err != nil {
+		return fmt.Errorf("invalid keepalive interval: %s", keepaliveIntervalStr)
+	}
+	managerInterval, err := util.ParseDuration(managerIntervalStr)
+	if err != nil {
+		return fmt.Errorf("invalid manager interval: %s", managerIntervalStr)
+	}
+	messageDelayLimit, err := util.ParseDuration(messageDelayLimitStr)
+	if err != nil {
+		return fmt.Errorf("invalid message delay limit: %s", messageDelayLimitStr)
+	}
+	visitorRequestLimitReplenish, err := util.ParseDuration(visitorRequestLimitReplenishStr)
+	if err != nil {
+		return fmt.Errorf("invalid visitor request limit replenish: %s", visitorRequestLimitReplenishStr)
+	}
+	visitorEmailLimitReplenish, err := util.ParseDuration(visitorEmailLimitReplenishStr)
+	if err != nil {
+		return fmt.Errorf("invalid visitor email limit replenish: %s", visitorEmailLimitReplenishStr)
+	}
+
+	// Convert sizes to bytes
+	messageSizeLimit, err := util.ParseSize(messageSizeLimitStr)
+	if err != nil {
+		return fmt.Errorf("invalid message size limit: %s", messageSizeLimitStr)
+	}
+	attachmentTotalSizeLimit, err := util.ParseSize(attachmentTotalSizeLimitStr)
+	if err != nil {
+		return fmt.Errorf("invalid attachment total size limit: %s", attachmentTotalSizeLimitStr)
+	}
+	attachmentFileSizeLimit, err := util.ParseSize(attachmentFileSizeLimitStr)
+	if err != nil {
+		return fmt.Errorf("invalid attachment file size limit: %s", attachmentFileSizeLimitStr)
+	}
+	visitorAttachmentTotalSizeLimit, err := util.ParseSize(visitorAttachmentTotalSizeLimitStr)
+	if err != nil {
+		return fmt.Errorf("invalid visitor attachment total size limit: %s", visitorAttachmentTotalSizeLimitStr)
+	}
+	visitorAttachmentDailyBandwidthLimit, err := util.ParseSize(visitorAttachmentDailyBandwidthLimitStr)
+	if err != nil {
+		return fmt.Errorf("invalid visitor attachment daily bandwidth limit: %s", visitorAttachmentDailyBandwidthLimitStr)
+	} else if visitorAttachmentDailyBandwidthLimit > math.MaxInt {
+		return fmt.Errorf("config option visitor-attachment-daily-bandwidth-limit must be lower than %d", math.MaxInt)
+	}
+
 	// Check values
 	if firebaseKeyFile != "" && !util.FileExists(firebaseKeyFile) {
 		return errors.New("if set, FCM key file must exist")
@@ -213,10 +274,15 @@ func execServe(c *cli.Context) error {
 		return errors.New("if smtp-server-listen is set, smtp-server-domain must also be set")
 	} else if attachmentCacheDir != "" && baseURL == "" {
 		return errors.New("if attachment-cache-dir is set, base-url must also be set")
-	} else if baseURL != "" && !strings.HasPrefix(baseURL, "http://") && !strings.HasPrefix(baseURL, "https://") {
-		return errors.New("if set, base-url must start with http:// or https://")
-	} else if baseURL != "" && strings.HasSuffix(baseURL, "/") {
-		return errors.New("if set, base-url must not end with a slash (/)")
+	} else if baseURL != "" {
+		u, err := url.Parse(baseURL)
+		if err != nil {
+			return fmt.Errorf("if set, base-url must be a valid URL, e.g. https://ntfy.mydomain.com: %v", err)
+		} else if u.Scheme != "http" && u.Scheme != "https" {
+			return errors.New("if set, base-url must be a valid URL starting with http:// or https://, e.g. https://ntfy.mydomain.com")
+		} else if u.Path != "" {
+			return fmt.Errorf("if set, base-url must not have a path (%s), as hosting ntfy on a sub-path is not supported, e.g. https://ntfy.mydomain.com", u.Path)
+		}
 	} else if upstreamBaseURL != "" && !strings.HasPrefix(upstreamBaseURL, "http://") && !strings.HasPrefix(upstreamBaseURL, "https://") {
 		return errors.New("if set, upstream-base-url must start with http:// or https://")
 	} else if upstreamBaseURL != "" && strings.HasSuffix(upstreamBaseURL, "/") {
@@ -233,6 +299,11 @@ func execServe(c *cli.Context) error {
 		return errors.New("if stripe-secret-key is set, stripe-webhook-key and base-url must also be set")
 	} else if twilioAccount != "" && (twilioAuthToken == "" || twilioPhoneNumber == "" || twilioVerifyService == "" || baseURL == "" || authFile == "") {
 		return errors.New("if twilio-account is set, twilio-auth-token, twilio-phone-number, twilio-verify-service, base-url, and auth-file must also be set")
+	} else if messageSizeLimit > server.DefaultMessageSizeLimit {
+		log.Warn("message-size-limit is greater than 4K, this is not recommended and largely untested, and may lead to issues with some clients")
+		if messageSizeLimit > 5*1024*1024 {
+			return errors.New("message-size-limit cannot be higher than 5M")
+		}
 	}
 
 	// Backwards compatibility
@@ -257,26 +328,6 @@ func execServe(c *cli.Context) error {
 		listenHTTP = ""
 	}
 
-	// Convert sizes to bytes
-	attachmentTotalSizeLimit, err := parseSize(attachmentTotalSizeLimitStr, server.DefaultAttachmentTotalSizeLimit)
-	if err != nil {
-		return err
-	}
-	attachmentFileSizeLimit, err := parseSize(attachmentFileSizeLimitStr, server.DefaultAttachmentFileSizeLimit)
-	if err != nil {
-		return err
-	}
-	visitorAttachmentTotalSizeLimit, err := parseSize(visitorAttachmentTotalSizeLimitStr, server.DefaultVisitorAttachmentTotalSizeLimit)
-	if err != nil {
-		return err
-	}
-	visitorAttachmentDailyBandwidthLimit, err := parseSize(visitorAttachmentDailyBandwidthLimitStr, server.DefaultVisitorAttachmentDailyBandwidthLimit)
-	if err != nil {
-		return err
-	} else if visitorAttachmentDailyBandwidthLimit > math.MaxInt {
-		return fmt.Errorf("config option visitor-attachment-daily-bandwidth-limit must be lower than %d", math.MaxInt)
-	}
-
 	// Resolve hosts
 	visitorRequestLimitExemptIPs := make([]netip.Prefix, 0)
 	for _, host := range visitorRequestLimitExemptHosts {
@@ -337,6 +388,8 @@ func execServe(c *cli.Context) error {
 	conf.TwilioAuthToken = twilioAuthToken
 	conf.TwilioPhoneNumber = twilioPhoneNumber
 	conf.TwilioVerifyService = twilioVerifyService
+	conf.MessageSizeLimit = int(messageSizeLimit)
+	conf.MessageDelayMax = messageDelayLimit
 	conf.TotalTopicLimit = totalTopicLimit
 	conf.VisitorSubscriptionLimit = visitorSubscriptionLimit
 	conf.VisitorAttachmentTotalSizeLimit = visitorAttachmentTotalSizeLimit
@@ -379,17 +432,6 @@ func execServe(c *cli.Context) error {
 	return nil
 }
 
-func parseSize(s string, defaultValue int64) (v int64, err error) {
-	if s == "" {
-		return defaultValue, nil
-	}
-	v, err = util.ParseSize(s)
-	if err != nil {
-		return 0, err
-	}
-	return v, nil
-}
-
 func sigHandlerConfigReload(config string) {
 	sigs := make(chan os.Signal, 1)
 	signal.Notify(sigs, syscall.SIGHUP)
diff --git a/cmd/tier.go b/cmd/tier.go
index 63b023f9..3b45eaa7 100644
--- a/cmd/tier.go
+++ b/cmd/tier.go
@@ -366,9 +366,9 @@ func printTier(c *cli.Context, tier *user.Tier) {
 	fmt.Fprintf(c.App.ErrWriter, "- Email limit: %d\n", tier.EmailLimit)
 	fmt.Fprintf(c.App.ErrWriter, "- Phone call limit: %d\n", tier.CallLimit)
 	fmt.Fprintf(c.App.ErrWriter, "- Reservation limit: %d\n", tier.ReservationLimit)
-	fmt.Fprintf(c.App.ErrWriter, "- Attachment file size limit: %s\n", util.FormatSize(tier.AttachmentFileSizeLimit))
-	fmt.Fprintf(c.App.ErrWriter, "- Attachment total size limit: %s\n", util.FormatSize(tier.AttachmentTotalSizeLimit))
+	fmt.Fprintf(c.App.ErrWriter, "- Attachment file size limit: %s\n", util.FormatSizeHuman(tier.AttachmentFileSizeLimit))
+	fmt.Fprintf(c.App.ErrWriter, "- Attachment total size limit: %s\n", util.FormatSizeHuman(tier.AttachmentTotalSizeLimit))
 	fmt.Fprintf(c.App.ErrWriter, "- Attachment expiry duration: %s (%d seconds)\n", tier.AttachmentExpiryDuration.String(), int64(tier.AttachmentExpiryDuration.Seconds()))
-	fmt.Fprintf(c.App.ErrWriter, "- Attachment daily bandwidth limit: %s\n", util.FormatSize(tier.AttachmentBandwidthLimit))
+	fmt.Fprintf(c.App.ErrWriter, "- Attachment daily bandwidth limit: %s\n", util.FormatSizeHuman(tier.AttachmentBandwidthLimit))
 	fmt.Fprintf(c.App.ErrWriter, "- Stripe prices (monthly/yearly): %s\n", prices)
 }
diff --git a/docs/config.md b/docs/config.md
index c987c27f..5fc1b6e5 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -995,6 +995,15 @@ are the easiest), and then configure the following options:
 After you have configured phone calls, create a [tier](#tiers) with a call limit (e.g. `ntfy tier create --call-limit=10 ...`),
 and then assign it to a user. Users may then use the `X-Call` header to receive a phone call when publishing a message.
 
+## Message limits
+There are a few message limits that you can configure:
+
+* `message-size-limit` defines the max size of a message body. Please note message sizes >4K are **not recommended,
+   and largely untested**. The Android/iOS and other clients may not work, or work properly. If FCM and/or APNS is used,
+   the limit should stay 4K, because their limits are around that size. If you increase this size limit regardless, 
+   FCM and APNS will NOT work for large messages.
+* `message-delay-limit` defines the max delay of a message when using the "Delay" header and [scheduled delivery](publish.md#scheduled-delivery).
+
 ## Rate limiting
 !!! info
     Be aware that if you are running ntfy behind a proxy, you must set the `behind-proxy` flag. 
@@ -1092,8 +1101,8 @@ response if no "rate visitor" has been previously registered. This is to avoid b
 To enable subscriber-based rate limiting, set `visitor-subscriber-rate-limiting: true`.
 
 !!! info
-    Due to a denial-of-service issue, support for the `Rate-Topics` header was removed entirely. This is unfortunate,
-    but subscriber-based rate limiting will still work for `up*` topics.
+    Due to a [denial-of-service issue](https://github.com/binwiederhier/ntfy/issues/1048), support for the `Rate-Topics`
+    header was removed entirely. This is unfortunate, but subscriber-based rate limiting will still work for `up*` topics.
 
 ## Tuning for scale
 If you're running ntfy for your home server, you probably don't need to worry about scale at all. In its default config,
@@ -1391,6 +1400,8 @@ variable before running the `ntfy` command (e.g. `export NTFY_LISTEN_HTTP=:80`).
 | `twilio-verify-service`                    | `NTFY_TWILIO_VERIFY_SERVICE`                    | *string*                                            | -                 | Twilio Verify service SID, e.g. VA12345beefbeef67890beefbeef122586                                                                                                                                                              |
 | `keepalive-interval`                       | `NTFY_KEEPALIVE_INTERVAL`                       | *duration*                                          | 45s               | Interval in which keepalive messages are sent to the client. This is to prevent intermediaries closing the connection for inactivity. Note that the Android app has a hardcoded timeout at 77s, so it should be less than that. |
 | `manager-interval`                         | `NTFY_MANAGER_INTERVAL`                         | *duration*                                          | 1m                | Interval in which the manager prunes old messages, deletes topics and prints the stats.                                                                                                                                         |
+| `message-size-limit`                       | `NTFY_MESSAGE_SIZE_LIMIT`                       | *size*                                              | 4K                | The size limit for the message body. Please note that this is largely untested, and that FCM/APNS have limits around 4KB. If you increase this size limit, FCM and APNS will NOT work for large messages.                       |
+| `message-delay-limit`                      | `NTFY_MESSAGE_DELAY_LIMIT`                      | *duration*                                          | 3d                | Amount of time a message can be [scheduled](publish.md#scheduled-delivery) into the future when using the `Delay` header                                                                                                        |
 | `global-topic-limit`                       | `NTFY_GLOBAL_TOPIC_LIMIT`                       | *number*                                            | 15,000            | Rate limiting: Total number of topics before the server rejects new topics.                                                                                                                                                     |
 | `upstream-base-url`                        | `NTFY_UPSTREAM_BASE_URL`                        | *URL*                                               | `https://ntfy.sh` | Forward poll request to an upstream server, this is needed for iOS push notifications for self-hosted servers                                                                                                                   |
 | `upstream-access-token`                    | `NTFY_UPSTREAM_ACCESS_TOKEN`                    | *string*                                            | `tk_zyYLYj...`    | Access token to use for the upstream server; needed only if upstream rate limits are exceeded or upstream server requires auth                                                                                                  |
@@ -1417,7 +1428,7 @@ variable before running the `ntfy` command (e.g. `export NTFY_LISTEN_HTTP=:80`).
 | `web-push-email-address`                   | `NTFY_WEB_PUSH_EMAIL_ADDRESS`                   | *string*                                            | -                 | Web Push: Sender email address                                                                                                                                                                                                  |
 | `web-push-startup-queries`                 | `NTFY_WEB_PUSH_STARTUP_QUERIES`                 | *string*                                            | -                 | Web Push: SQL queries to run against subscription database at startup                                                                                                                                                           |
 
-The format for a *duration* is: `<number>(smh)`, e.g. 30s, 20m or 1h.   
+The format for a *duration* is: `<number>(smhd)`, e.g. 30s, 20m, 1h or 3d.   
 The format for a *size* is: `<number>(GMK)`, e.g. 1G, 200M or 4000k.
 
 ## Command line options
@@ -1449,7 +1460,7 @@ OPTIONS:
    --log-level-overrides value, --log_level_overrides value [ --log-level-overrides value, --log_level_overrides value ]  set log level overrides [$NTFY_LOG_LEVEL_OVERRIDES]
    --log-format value, --log_format value                                                                                 set log format (default: "text") [$NTFY_LOG_FORMAT]
    --log-file value, --log_file value                                                                                     set log file, default is STDOUT [$NTFY_LOG_FILE]
-   --config value, -c value                                                                                               config file (default: /etc/ntfy/server.yml) [$NTFY_CONFIG_FILE]
+   --config value, -c value                                                                                               config file (default: "/etc/ntfy/server.yml") [$NTFY_CONFIG_FILE]
    --base-url value, --base_url value, -B value                                                                           externally visible base URL for this host (e.g. https://ntfy.sh) [$NTFY_BASE_URL]
    --listen-http value, --listen_http value, -l value                                                                     ip:port used as HTTP listen address (default: ":80") [$NTFY_LISTEN_HTTP]
    --listen-https value, --listen_https value, -L value                                                                   ip:port used as HTTPS listen address [$NTFY_LISTEN_HTTPS]
@@ -1459,19 +1470,19 @@ OPTIONS:
    --cert-file value, --cert_file value, -E value                                                                         certificate file, if listen-https is set [$NTFY_CERT_FILE]
    --firebase-key-file value, --firebase_key_file value, -F value                                                         Firebase credentials file; if set additionally publish to FCM topic [$NTFY_FIREBASE_KEY_FILE]
    --cache-file value, --cache_file value, -C value                                                                       cache file used for message caching [$NTFY_CACHE_FILE]
-   --cache-duration since, --cache_duration since, -b since                                                               buffer messages for this time to allow since requests (default: 12h0m0s) [$NTFY_CACHE_DURATION]
+   --cache-duration since, --cache_duration since, -b since                                                               buffer messages for this time to allow since requests (default: "12h") [$NTFY_CACHE_DURATION]
    --cache-batch-size value, --cache_batch_size value                                                                     max size of messages to batch together when writing to message cache (if zero, writes are synchronous) (default: 0) [$NTFY_BATCH_SIZE]
-   --cache-batch-timeout value, --cache_batch_timeout value                                                               timeout for batched async writes to the message cache (if zero, writes are synchronous) (default: 0s) [$NTFY_CACHE_BATCH_TIMEOUT]
+   --cache-batch-timeout value, --cache_batch_timeout value                                                               timeout for batched async writes to the message cache (if zero, writes are synchronous) (default: "0s") [$NTFY_CACHE_BATCH_TIMEOUT]
    --cache-startup-queries value, --cache_startup_queries value                                                           queries run when the cache database is initialized [$NTFY_CACHE_STARTUP_QUERIES]
    --auth-file value, --auth_file value, -H value                                                                         auth database file used for access control [$NTFY_AUTH_FILE]
    --auth-startup-queries value, --auth_startup_queries value                                                             queries run when the auth database is initialized [$NTFY_AUTH_STARTUP_QUERIES]
    --auth-default-access value, --auth_default_access value, -p value                                                     default permissions if no matching entries in the auth database are found (default: "read-write") [$NTFY_AUTH_DEFAULT_ACCESS]
    --attachment-cache-dir value, --attachment_cache_dir value                                                             cache directory for attached files [$NTFY_ATTACHMENT_CACHE_DIR]
-   --attachment-total-size-limit value, --attachment_total_size_limit value, -A value                                     limit of the on-disk attachment cache (default: 5G) [$NTFY_ATTACHMENT_TOTAL_SIZE_LIMIT]
-   --attachment-file-size-limit value, --attachment_file_size_limit value, -Y value                                       per-file attachment size limit (e.g. 300k, 2M, 100M) (default: 15M) [$NTFY_ATTACHMENT_FILE_SIZE_LIMIT]
-   --attachment-expiry-duration value, --attachment_expiry_duration value, -X value                                       duration after which uploaded attachments will be deleted (e.g. 3h, 20h) (default: 3h) [$NTFY_ATTACHMENT_EXPIRY_DURATION]
-   --keepalive-interval value, --keepalive_interval value, -k value                                                       interval of keepalive messages (default: 45s) [$NTFY_KEEPALIVE_INTERVAL]
-   --manager-interval value, --manager_interval value, -m value                                                           interval of for message pruning and stats printing (default: 1m0s) [$NTFY_MANAGER_INTERVAL]
+   --attachment-total-size-limit value, --attachment_total_size_limit value, -A value                                     limit of the on-disk attachment cache (default: "5G") [$NTFY_ATTACHMENT_TOTAL_SIZE_LIMIT]
+   --attachment-file-size-limit value, --attachment_file_size_limit value, -Y value                                       per-file attachment size limit (e.g. 300k, 2M, 100M) (default: "15M") [$NTFY_ATTACHMENT_FILE_SIZE_LIMIT]
+   --attachment-expiry-duration value, --attachment_expiry_duration value, -X value                                       duration after which uploaded attachments will be deleted (e.g. 3h, 20h) (default: "3h") [$NTFY_ATTACHMENT_EXPIRY_DURATION]
+   --keepalive-interval value, --keepalive_interval value, -k value                                                       interval of keepalive messages (default: "45s") [$NTFY_KEEPALIVE_INTERVAL]
+   --manager-interval value, --manager_interval value, -m value                                                           interval of for message pruning and stats printing (default: "1m") [$NTFY_MANAGER_INTERVAL]
    --disallowed-topics value, --disallowed_topics value [ --disallowed-topics value, --disallowed_topics value ]          topics that are not allowed to be used [$NTFY_DISALLOWED_TOPICS]
    --web-root value, --web_root value                                                                                     sets root of the web app (e.g. /, or /app), or disables it (disable) (default: "/") [$NTFY_WEB_ROOT]
    --enable-signup, --enable_signup                                                                                       allows users to sign up via the web app, or API (default: false) [$NTFY_ENABLE_SIGNUP]
@@ -1490,16 +1501,18 @@ OPTIONS:
    --twilio-auth-token value, --twilio_auth_token value                                                                   Twilio auth token [$NTFY_TWILIO_AUTH_TOKEN]
    --twilio-phone-number value, --twilio_phone_number value                                                               Twilio number to use for outgoing calls [$NTFY_TWILIO_PHONE_NUMBER]
    --twilio-verify-service value, --twilio_verify_service value                                                           Twilio Verify service ID, used for phone number verification [$NTFY_TWILIO_VERIFY_SERVICE]
+   --message-size-limit value, --message_size_limit value                                                                 size limit for the message (see docs for limitations) (default: "4K") [$NTFY_MESSAGE_SIZE_LIMIT]
+   --message-delay-limit value, --message_delay_limit value                                                               max duration a message can be scheduled into the future (default: "3d") [$NTFY_MESSAGE_DELAY_LIMIT]
    --global-topic-limit value, --global_topic_limit value, -T value                                                       total number of topics allowed (default: 15000) [$NTFY_GLOBAL_TOPIC_LIMIT]
    --visitor-subscription-limit value, --visitor_subscription_limit value                                                 number of subscriptions per visitor (default: 30) [$NTFY_VISITOR_SUBSCRIPTION_LIMIT]
    --visitor-attachment-total-size-limit value, --visitor_attachment_total_size_limit value                               total storage limit used for attachments per visitor (default: "100M") [$NTFY_VISITOR_ATTACHMENT_TOTAL_SIZE_LIMIT]
    --visitor-attachment-daily-bandwidth-limit value, --visitor_attachment_daily_bandwidth_limit value                     total daily attachment download/upload bandwidth limit per visitor (default: "500M") [$NTFY_VISITOR_ATTACHMENT_DAILY_BANDWIDTH_LIMIT]
    --visitor-request-limit-burst value, --visitor_request_limit_burst value                                               initial limit of requests per visitor (default: 60) [$NTFY_VISITOR_REQUEST_LIMIT_BURST]
-   --visitor-request-limit-replenish value, --visitor_request_limit_replenish value                                       interval at which burst limit is replenished (one per x) (default: 5s) [$NTFY_VISITOR_REQUEST_LIMIT_REPLENISH]
+   --visitor-request-limit-replenish value, --visitor_request_limit_replenish value                                       interval at which burst limit is replenished (one per x) (default: "5s") [$NTFY_VISITOR_REQUEST_LIMIT_REPLENISH]
    --visitor-request-limit-exempt-hosts value, --visitor_request_limit_exempt_hosts value                                 hostnames and/or IP addresses of hosts that will be exempt from the visitor request limit [$NTFY_VISITOR_REQUEST_LIMIT_EXEMPT_HOSTS]
    --visitor-message-daily-limit value, --visitor_message_daily_limit value                                               max messages per visitor per day, derived from request limit if unset (default: 0) [$NTFY_VISITOR_MESSAGE_DAILY_LIMIT]
    --visitor-email-limit-burst value, --visitor_email_limit_burst value                                                   initial limit of e-mails per visitor (default: 16) [$NTFY_VISITOR_EMAIL_LIMIT_BURST]
-   --visitor-email-limit-replenish value, --visitor_email_limit_replenish value                                           interval at which burst limit is replenished (one per x) (default: 1h0m0s) [$NTFY_VISITOR_EMAIL_LIMIT_REPLENISH]
+   --visitor-email-limit-replenish value, --visitor_email_limit_replenish value                                           interval at which burst limit is replenished (one per x) (default: "1h") [$NTFY_VISITOR_EMAIL_LIMIT_REPLENISH]
    --visitor-subscriber-rate-limiting, --visitor_subscriber_rate_limiting                                                 enables subscriber-based rate limiting (default: false) [$NTFY_VISITOR_SUBSCRIBER_RATE_LIMITING]
    --behind-proxy, --behind_proxy, -P                                                                                     if set, use X-Forwarded-For header to determine visitor IP address (for rate limiting) (default: false) [$NTFY_BEHIND_PROXY]
    --stripe-secret-key value, --stripe_secret_key value                                                                   key used for the Stripe API communication, this enables payments [$NTFY_STRIPE_SECRET_KEY]
@@ -1512,6 +1525,6 @@ OPTIONS:
    --web-push-private-key value, --web_push_private_key value                                                             private key used for web push notifications [$NTFY_WEB_PUSH_PRIVATE_KEY]
    --web-push-file value, --web_push_file value                                                                           file used to store web push subscriptions [$NTFY_WEB_PUSH_FILE]
    --web-push-email-address value, --web_push_email_address value                                                         e-mail address of sender, required to use browser push services [$NTFY_WEB_PUSH_EMAIL_ADDRESS]
-   --web-push-startup-queries value, --web_push_startup-queries value                                                     queries run when the web push database is initialized [$NTFY_WEB_PUSH_STARTUP_QUERIES]   
+   --web-push-startup-queries value, --web_push_startup_queries value                                                     queries run when the web push database is initialized [$NTFY_WEB_PUSH_STARTUP_QUERIES]
    --help, -h                                                                                                             show help
 ```
diff --git a/docs/publish.md b/docs/publish.md
index 41370778..41109290 100644
--- a/docs/publish.md
+++ b/docs/publish.md
@@ -738,9 +738,8 @@ Usage is pretty straight forward. You can set the delivery time using the `X-Del
 `3h`, `2 days`), or a natural language time string (e.g. `10am`, `8:30pm`, `tomorrow, 3pm`, `Tuesday, 7am`, 
 [and more](https://github.com/olebedev/when)). 
 
-As of today, the minimum delay you can set is **10 seconds** and the maximum delay is **3 days**. This can currently
-not be configured otherwise ([let me know](https://github.com/binwiederhier/ntfy/issues) if you'd like to change 
-these limits).
+As of today, the minimum delay you can set is **10 seconds** and the maximum delay is **3 days**. This can be configured
+with the `message-delay-limit` option).
 
 For the purposes of [message caching](config.md#message-cache), scheduled messages are kept in the cache until 12 hours 
 after they were delivered (or whatever the server-side cache duration is set to). For instance, if a message is scheduled
diff --git a/docs/releases.md b/docs/releases.md
index 3549330b..7285ebba 100644
--- a/docs/releases.md
+++ b/docs/releases.md
@@ -13,7 +13,7 @@ Many thanks to [@tcaputi](https://github.com/tcaputi) for fixing the issues, and
 
 * UI not updating properly ([#267](https://github.com/binwiederhier/ntfy/issues/267)/[#402](https://github.com/binwiederhier/ntfy/issues/402), thanks to [@tcaputi](https://github.com/tcaputi))
 
-### ntfy server v2.8.0
+## ntfy server v2.8.0
 Released November 19, 2023
 
 This release brings a handful of random bug fixes: two unrelated access control list fixes, a fix around web app crashes for languages with underscores in the language code (e.g. `zh_Hant`, `zh_Hans`, `pt_BR`, ...), a workaround for the `Priority` header (often used in Cloudflare setups), and support among others support for HTML-only emails (finally), web app crash fixes 
@@ -1315,6 +1315,14 @@ and the [ntfy Android app](https://github.com/binwiederhier/ntfy-android/release
 
 ### ntfy server v2.9.0
 
+!!! info
+    **Breaking change**: The `Rate-Topics` header was removed due to a [DoS issue](https://github.com/binwiederhier/ntfy/issues/1048). This only affects installations with `visitor-subscriber-rate-limiting: true`, which is not the default and likely very rarely used.
+
+**Features:**
+
+* Support for larger message delays with `message-delay-limit` (see [message limits](config.md#message-limits), [#1050](https://github.com/binwiederhier/ntfy/pull/1050)/[#1019](https://github.com/binwiederhier/ntfy/issues/1019), thanks to [@MrChadMWood](https://github.com/MrChadMWood) for reporting)
+* Support for larger message body sizes with `message-size-limit` (use at your own risk, see [message limits](config.md#message-limits), [#836](https://github.com/binwiederhier/ntfy/pull/836)/[#1050](https://github.com/binwiederhier/ntfy/pull/1050), thanks to [@zhzy0077](https://github.com/zhzy0077) for implementing this, and to [@nkjshlsqja7331](https://github.com/nkjshlsqja7331) for reporting)
+
 **Bug fixes + maintenance:**
 
 * Remove `Rate-Topics` header due to DoS security issue if `visitor-subscriber-rate-limiting: true` ([#1048](https://github.com/binwiederhier/ntfy/issues/1048)) 
diff --git a/server/config.go b/server/config.go
index a0cfdcd5..7267ce9d 100644
--- a/server/config.go
+++ b/server/config.go
@@ -12,11 +12,12 @@ import (
 const (
 	DefaultListenHTTP                           = ":80"
 	DefaultCacheDuration                        = 12 * time.Hour
+	DefaultCacheBatchTimeout                    = time.Duration(0)
 	DefaultKeepaliveInterval                    = 45 * time.Second // Not too frequently to save battery (Android read timeout used to be 77s!)
 	DefaultManagerInterval                      = time.Minute
 	DefaultDelayedSenderInterval                = 10 * time.Second
-	DefaultMinDelay                             = 10 * time.Second
-	DefaultMaxDelay                             = 3 * 24 * time.Hour
+	DefaultMessageDelayMin                      = 10 * time.Second
+	DefaultMessageDelayMax                      = 3 * 24 * time.Hour
 	DefaultFirebaseKeepaliveInterval            = 3 * time.Hour    // ~control topic (Android), not too frequently to save battery
 	DefaultFirebasePollInterval                 = 20 * time.Minute // ~poll topic (iOS), max. 2-3 times per hour (see docs)
 	DefaultFirebaseQuotaExceededPenaltyDuration = 10 * time.Minute // Time that over-users are locked out of Firebase if it returns "quota exceeded"
@@ -34,7 +35,7 @@ const (
 // - total topic limit: max number of topics overall
 // - various attachment limits
 const (
-	DefaultMessageLengthLimit       = 4096 // Bytes
+	DefaultMessageSizeLimit         = 4096 // Bytes; note that FCM/APNS have a limit of ~4 KB for the entire message
 	DefaultTotalTopicLimit          = 15000
 	DefaultAttachmentTotalSizeLimit = int64(5 * 1024 * 1024 * 1024) // 5 GB
 	DefaultAttachmentFileSizeLimit  = int64(15 * 1024 * 1024)       // 15 MB
@@ -122,9 +123,9 @@ type Config struct {
 	MetricsEnable                        bool
 	MetricsListenHTTP                    string
 	ProfileListenHTTP                    string
-	MessageLimit                         int
-	MinDelay                             time.Duration
-	MaxDelay                             time.Duration
+	MessageDelayMin                      time.Duration
+	MessageDelayMax                      time.Duration
+	MessageSizeLimit                     int
 	TotalTopicLimit                      int
 	TotalAttachmentSizeLimit             int64
 	VisitorSubscriptionLimit             int
@@ -211,9 +212,9 @@ func NewConfig() *Config {
 		TwilioPhoneNumber:                    "",
 		TwilioVerifyBaseURL:                  "https://verify.twilio.com", // Override for tests
 		TwilioVerifyService:                  "",
-		MessageLimit:                         DefaultMessageLengthLimit,
-		MinDelay:                             DefaultMinDelay,
-		MaxDelay:                             DefaultMaxDelay,
+		MessageSizeLimit:                     DefaultMessageSizeLimit,
+		MessageDelayMin:                      DefaultMessageDelayMin,
+		MessageDelayMax:                      DefaultMessageDelayMax,
 		TotalTopicLimit:                      DefaultTotalTopicLimit,
 		TotalAttachmentSizeLimit:             0,
 		VisitorSubscriptionLimit:             DefaultVisitorSubscriptionLimit,
diff --git a/server/server.go b/server/server.go
index aad452ed..f6e39be3 100644
--- a/server/server.go
+++ b/server/server.go
@@ -733,7 +733,7 @@ func (s *Server) handlePublishInternal(r *http.Request, v *visitor) (*message, e
 	if err != nil {
 		return nil, err
 	}
-	body, err := util.Peek(r.Body, s.config.MessageLimit)
+	body, err := util.Peek(r.Body, s.config.MessageSizeLimit)
 	if err != nil {
 		return nil, err
 	}
@@ -996,9 +996,9 @@ func (s *Server) parsePublishParams(r *http.Request, m *message) (cache bool, fi
 		delay, err := util.ParseFutureTime(delayStr, time.Now())
 		if err != nil {
 			return false, false, "", "", false, errHTTPBadRequestDelayCannotParse
-		} else if delay.Unix() < time.Now().Add(s.config.MinDelay).Unix() {
+		} else if delay.Unix() < time.Now().Add(s.config.MessageDelayMin).Unix() {
 			return false, false, "", "", false, errHTTPBadRequestDelayTooSmall
-		} else if delay.Unix() > time.Now().Add(s.config.MaxDelay).Unix() {
+		} else if delay.Unix() > time.Now().Add(s.config.MessageDelayMax).Unix() {
 			return false, false, "", "", false, errHTTPBadRequestDelayTooLarge
 		}
 		m.Time = delay.Unix()
@@ -1754,7 +1754,7 @@ func (s *Server) sendDelayedMessage(v *visitor, m *message) error {
 // before passing it on to the next handler. This is meant to be used in combination with handlePublish.
 func (s *Server) transformBodyJSON(next handleFunc) handleFunc {
 	return func(w http.ResponseWriter, r *http.Request, v *visitor) error {
-		m, err := readJSONWithLimit[publishMessage](r.Body, s.config.MessageLimit*2, false) // 2x to account for JSON format overhead
+		m, err := readJSONWithLimit[publishMessage](r.Body, s.config.MessageSizeLimit*2, false) // 2x to account for JSON format overhead
 		if err != nil {
 			return err
 		}
@@ -1812,7 +1812,7 @@ func (s *Server) transformBodyJSON(next handleFunc) handleFunc {
 
 func (s *Server) transformMatrixJSON(next handleFunc) handleFunc {
 	return func(w http.ResponseWriter, r *http.Request, v *visitor) error {
-		newRequest, err := newRequestFromMatrixJSON(r, s.config.BaseURL, s.config.MessageLimit)
+		newRequest, err := newRequestFromMatrixJSON(r, s.config.BaseURL, s.config.MessageSizeLimit)
 		if err != nil {
 			logvr(v, r).Tag(tagMatrix).Err(err).Debug("Invalid Matrix request")
 			if e, ok := err.(*errMatrixPushkeyRejected); ok {
diff --git a/server/server.yml b/server/server.yml
index e9e55e9b..7329d37e 100644
--- a/server/server.yml
+++ b/server/server.yml
@@ -236,6 +236,16 @@
 # upstream-base-url:
 # upstream-access-token:
 
+# Configures message-specific limits
+#
+# - message-size-limit defines the max size of a message body. Please note message sizes >4K are NOT RECOMMENDED,
+#   and largely untested. If FCM and/or APNS is used, the limit should stay 4K, because their limits are around that size.
+#   If you increase this size limit regardless, FCM and APNS will NOT work for large messages.
+# - message-delay-limit defines the max delay of a message when using the "Delay" header.
+#
+# message-size-limit: "4k"
+# message-delay-limit: "3d"
+
 # Rate limiting: Total number of topics before the server rejects new topics.
 #
 # global-topic-limit: 15000
diff --git a/server/server_account_test.go b/server/server_account_test.go
index 4c269c2f..72ba55c9 100644
--- a/server/server_account_test.go
+++ b/server/server_account_test.go
@@ -718,11 +718,11 @@ func TestAccount_Reservation_Delete_Messages_And_Attachments(t *testing.T) {
 	require.Nil(t, s.userManager.AddUser("phil", "phil", user.RoleUser))
 	require.Nil(t, s.userManager.AddTier(&user.Tier{
 		Code:         "starter",
-		MessageLimit: 10,
+		MessageSizeLimit: 10,
 	}))
 	require.Nil(t, s.userManager.AddTier(&user.Tier{
 		Code:         "pro",
-		MessageLimit: 20,
+		MessageSizeLimit: 20,
 	}))
 	require.Nil(t, s.userManager.ChangeTier("phil", "starter"))
 
diff --git a/server/smtp_server.go b/server/smtp_server.go
index 467b8ca4..a687f1da 100644
--- a/server/smtp_server.go
+++ b/server/smtp_server.go
@@ -150,8 +150,8 @@ func (s *smtpSession) Data(r io.Reader) error {
 			return err
 		}
 		body = strings.TrimSpace(body)
-		if len(body) > conf.MessageLimit {
-			body = body[:conf.MessageLimit]
+		if len(body) > conf.MessageSizeLimit {
+			body = body[:conf.MessageSizeLimit]
 		}
 		m := newDefaultMessage(s.topic, body)
 		subject := strings.TrimSpace(msg.Header.Get("Subject"))
diff --git a/server/visitor.go b/server/visitor.go
index f8dc416a..d542e773 100644
--- a/server/visitor.go
+++ b/server/visitor.go
@@ -30,10 +30,10 @@ const (
 	visitorDefaultCallsLimit = int64(0)
 )
 
-// Constants used to convert a tier-user's MessageLimit (see user.Tier) into adequate request limiter
+// Constants used to convert a tier-user's MessageSizeLimit (see user.Tier) into adequate request limiter
 // values (token bucket). This is only used to increase the values in server.yml, never decrease them.
 //
-// Example: Assuming a user.Tier's MessageLimit is 10,000:
+// Example: Assuming a user.Tier's MessageSizeLimit is 10,000:
 // - the allowed burst is 500 (= 10,000 * 5%), which is < 1000 (the max)
 // - the replenish rate is 2 * 10,000 / 24 hours
 const (
diff --git a/util/time.go b/util/time.go
index 14aa3936..9fbee890 100644
--- a/util/time.go
+++ b/util/time.go
@@ -10,8 +10,8 @@ import (
 )
 
 var (
-	errUnparsableTime = errors.New("unable to parse time")
-	durationStrRegex  = regexp.MustCompile(`(?i)^(\d+)\s*(d|days?|h|hours?|m|mins?|minutes?|s|secs?|seconds?)$`)
+	errInvalidDuration = errors.New("unable to parse duration")
+	durationStrRegex   = regexp.MustCompile(`(?i)^(\d+)\s*(d|days?|h|hours?|m|mins?|minutes?|s|secs?|seconds?)$`)
 )
 
 const (
@@ -51,7 +51,7 @@ func ParseFutureTime(s string, now time.Time) (time.Time, error) {
 	if err == nil {
 		return t, nil
 	}
-	return time.Time{}, errUnparsableTime
+	return time.Time{}, errInvalidDuration
 }
 
 // ParseDuration is like time.ParseDuration, except that it also understands days (d), which
@@ -65,7 +65,7 @@ func ParseDuration(s string) (time.Duration, error) {
 	if matches != nil {
 		number, err := strconv.Atoi(matches[1])
 		if err != nil {
-			return 0, errUnparsableTime
+			return 0, errInvalidDuration
 		}
 		switch unit := matches[2][0:1]; unit {
 		case "d":
@@ -77,10 +77,28 @@ func ParseDuration(s string) (time.Duration, error) {
 		case "s":
 			return time.Duration(number) * time.Second, nil
 		default:
-			return 0, errUnparsableTime
+			return 0, errInvalidDuration
 		}
 	}
-	return 0, errUnparsableTime
+	return 0, errInvalidDuration
+}
+
+// FormatDuration formats a time.Duration into a human-readable string, e.g. "2d", "20h", "30m", "40s".
+// It rounds to the largest unit that is not zero, thereby effectively rounding down.
+func FormatDuration(d time.Duration) string {
+	if d >= 24*time.Hour {
+		return strconv.Itoa(int(d/(24*time.Hour))) + "d"
+	}
+	if d >= time.Hour {
+		return strconv.Itoa(int(d/time.Hour)) + "h"
+	}
+	if d >= time.Minute {
+		return strconv.Itoa(int(d/time.Minute)) + "m"
+	}
+	if d >= time.Second {
+		return strconv.Itoa(int(d/time.Second)) + "s"
+	}
+	return "0s"
 }
 
 func parseFromDuration(s string, now time.Time) (time.Time, error) {
@@ -88,7 +106,7 @@ func parseFromDuration(s string, now time.Time) (time.Time, error) {
 	if err == nil {
 		return now.Add(d), nil
 	}
-	return time.Time{}, errUnparsableTime
+	return time.Time{}, errInvalidDuration
 }
 
 func parseUnixTime(s string, now time.Time) (time.Time, error) {
@@ -96,7 +114,7 @@ func parseUnixTime(s string, now time.Time) (time.Time, error) {
 	if err != nil {
 		return time.Time{}, err
 	} else if int64(t) < now.Unix() {
-		return time.Time{}, errUnparsableTime
+		return time.Time{}, errInvalidDuration
 	}
 	return time.Unix(int64(t), 0).UTC(), nil
 }
@@ -104,7 +122,7 @@ func parseUnixTime(s string, now time.Time) (time.Time, error) {
 func parseNaturalTime(s string, now time.Time) (time.Time, error) {
 	r, err := when.EN.Parse(s, now) // returns "nil, nil" if no matches!
 	if err != nil || r == nil {
-		return time.Time{}, errUnparsableTime
+		return time.Time{}, errInvalidDuration
 	} else if r.Time.After(now) {
 		return r.Time, nil
 	}
@@ -112,9 +130,9 @@ func parseNaturalTime(s string, now time.Time) (time.Time, error) {
 	// simply append "tomorrow, " to it.
 	r, err = when.EN.Parse("tomorrow, "+s, now) // returns "nil, nil" if no matches!
 	if err != nil || r == nil {
-		return time.Time{}, errUnparsableTime
+		return time.Time{}, errInvalidDuration
 	} else if r.Time.After(now) {
 		return r.Time, nil
 	}
-	return time.Time{}, errUnparsableTime
+	return time.Time{}, errInvalidDuration
 }
diff --git a/util/time_test.go b/util/time_test.go
index 9cc343fd..e29e5a3b 100644
--- a/util/time_test.go
+++ b/util/time_test.go
@@ -92,3 +92,27 @@ func TestParseDuration(t *testing.T) {
 	require.Nil(t, err)
 	require.Equal(t, time.Duration(0), d)
 }
+
+func TestFormatDuration(t *testing.T) {
+	values := []struct {
+		duration time.Duration
+		expected string
+	}{
+		{24 * time.Second, "24s"},
+		{56 * time.Minute, "56m"},
+		{time.Hour, "1h"},
+		{2 * time.Hour, "2h"},
+		{24 * time.Hour, "1d"},
+		{3 * 24 * time.Hour, "3d"},
+	}
+	for _, value := range values {
+		require.Equal(t, value.expected, FormatDuration(value.duration))
+		d, err := ParseDuration(FormatDuration(value.duration))
+		require.Nil(t, err)
+		require.Equalf(t, value.duration, d, "duration does not match: %v != %v", value.duration, d)
+	}
+}
+
+func TestFormatDuration_Rounded(t *testing.T) {
+	require.Equal(t, "1d", FormatDuration(47*time.Hour))
+}
diff --git a/util/util.go b/util/util.go
index df0c011c..39bf8798 100644
--- a/util/util.go
+++ b/util/util.go
@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"math"
 	"math/rand"
 	"net/netip"
 	"os"
@@ -215,6 +216,8 @@ func ParseSize(s string) (int64, error) {
 		return -1, fmt.Errorf("cannot convert number %s", matches[1])
 	}
 	switch strings.ToUpper(matches[2]) {
+	case "T":
+		return int64(value) * 1024 * 1024 * 1024 * 1024, nil
 	case "G":
 		return int64(value) * 1024 * 1024 * 1024, nil
 	case "M":
@@ -226,8 +229,23 @@ func ParseSize(s string) (int64, error) {
 	}
 }
 
-// FormatSize formats bytes into a human-readable notation, e.g. 2.1 MB
+// FormatSize formats the size in a way that it can be parsed by ParseSize.
+// It does not include decimal places. Uneven sizes are rounded down.
 func FormatSize(b int64) string {
+	const unit = 1024
+	if b < unit {
+		return fmt.Sprintf("%d", b)
+	}
+	div, exp := int64(unit), 0
+	for n := b / unit; n >= unit; n /= unit {
+		div *= unit
+		exp++
+	}
+	return fmt.Sprintf("%d%c", int(math.Floor(float64(b)/float64(div))), "KMGT"[exp])
+}
+
+// FormatSizeHuman formats bytes into a human-readable notation, e.g. 2.1 MB
+func FormatSizeHuman(b int64) string {
 	const unit = 1024
 	if b < unit {
 		return fmt.Sprintf("%d bytes", b)
@@ -237,7 +255,7 @@ func FormatSize(b int64) string {
 		div *= unit
 		exp++
 	}
-	return fmt.Sprintf("%.1f %cB", float64(b)/float64(div), "KMGTPE"[exp])
+	return fmt.Sprintf("%.1f %cB", float64(b)/float64(div), "KMGT"[exp])
 }
 
 // ReadPassword will read a password from STDIN. If the terminal supports it, it will not print the
diff --git a/util/util_test.go b/util/util_test.go
index f0f45c28..9ddec58d 100644
--- a/util/util_test.go
+++ b/util/util_test.go
@@ -110,33 +110,47 @@ func TestShortTopicURL(t *testing.T) {
 
 func TestParseSize_10GSuccess(t *testing.T) {
 	s, err := ParseSize("10G")
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.Nil(t, err)
 	require.Equal(t, int64(10*1024*1024*1024), s)
 }
 
 func TestParseSize_10MUpperCaseSuccess(t *testing.T) {
 	s, err := ParseSize("10M")
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.Nil(t, err)
 	require.Equal(t, int64(10*1024*1024), s)
 }
 
 func TestParseSize_10kLowerCaseSuccess(t *testing.T) {
 	s, err := ParseSize("10k")
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.Nil(t, err)
 	require.Equal(t, int64(10*1024), s)
 }
 
 func TestParseSize_FailureInvalid(t *testing.T) {
 	_, err := ParseSize("not a size")
-	if err == nil {
-		t.Fatalf("expected error, but got none")
+	require.Error(t, err)
+}
+
+func TestFormatSize(t *testing.T) {
+	values := []struct {
+		size     int64
+		expected string
+	}{
+		{10, "10"},
+		{10 * 1024, "10K"},
+		{10 * 1024 * 1024, "10M"},
+		{10 * 1024 * 1024 * 1024, "10G"},
 	}
+	for _, value := range values {
+		require.Equal(t, value.expected, FormatSize(value.size))
+		s, err := ParseSize(FormatSize(value.size))
+		require.Nil(t, err)
+		require.Equalf(t, value.size, s, "size does not match: %d != %d", value.size, s)
+	}
+}
+
+func TestFormatSize_Rounded(t *testing.T) {
+	require.Equal(t, "10K", FormatSize(10*1024+999))
 }
 
 func TestSplitKV(t *testing.T) {