diff --git a/irc/caps/constants.go b/irc/caps/constants.go
index 00e60a74..314abb68 100644
--- a/irc/caps/constants.go
+++ b/irc/caps/constants.go
@@ -36,6 +36,8 @@ const (
 	MaxLine Capability = "oragono.io/maxline"
 	// MessageTags is this draft IRCv3 capability: http://ircv3.net/specs/core/message-tags-3.3.html
 	MessageTags Capability = "draft/message-tags-0.2"
+	// Metadata is this draft IRCv3 capability: https://github.com/jwheare/ircv3-specifications/blob/metadata/core/metadata-3.2.md
+	Metadata Capability = "draft/metadata"
 	// MultiPrefix is this IRCv3 capability: http://ircv3.net/specs/extensions/multi-prefix-3.1.html
 	MultiPrefix Capability = "multi-prefix"
 	// Rename is this proposed capability: https://github.com/SaberUK/ircv3-specifications/blob/rename/extensions/rename.md
diff --git a/irc/channel.go b/irc/channel.go
index b082926c..288b0456 100644
--- a/irc/channel.go
+++ b/irc/channel.go
@@ -25,6 +25,7 @@ type Channel struct {
 	members           MemberSet
 	membersCache      []*Client  // allow iteration over channel members without holding the lock
 	membersCacheMutex sync.Mutex // tier 2; see `regenerateMembersCache`
+	metadata          *MetadataManager
 	name              string
 	nameCasefolded    string
 	server            *Server
@@ -56,6 +57,7 @@ func NewChannel(s *Server, name string, addDefaultModes bool, regInfo *Registere
 			modes.InviteMask: NewUserMaskSet(),
 		},
 		members:        make(MemberSet),
+		metadata:       NewMetadataManager(),
 		name:           name,
 		nameCasefolded: casefoldedName,
 		server:         s,
diff --git a/irc/client.go b/irc/client.go
index d309102a..79ab0cb0 100644
--- a/irc/client.go
+++ b/irc/client.go
@@ -60,6 +60,7 @@ type Client struct {
 	languages          []string
 	maxlenTags         uint32
 	maxlenRest         uint32
+	metadata           *MetadataManager
 	nick               string
 	nickCasefolded     string
 	nickMaskCasefolded string
@@ -100,6 +101,7 @@ func NewClient(server *Server, conn net.Conn, isTLS bool) *Client {
 		channels:       make(ChannelSet),
 		ctime:          now,
 		flags:          make(map[modes.Mode]bool),
+		metadata:       NewMetadataManager(),
 		server:         server,
 		socket:         &socket,
 		nick:           "*", // * is used until actual nick is given
diff --git a/irc/commands.go b/irc/commands.go
index 9970af68..9e1cf498 100644
--- a/irc/commands.go
+++ b/irc/commands.go
@@ -161,6 +161,10 @@ func init() {
 			handler:   lusersHandler,
 			minParams: 0,
 		},
+		"METADATA": {
+			handler:   metadataHandler,
+			minParams: 2,
+		},
 		"MODE": {
 			handler:   modeHandler,
 			minParams: 1,
diff --git a/irc/errors.go b/irc/errors.go
index 9354d59a..32edff71 100644
--- a/irc/errors.go
+++ b/irc/errors.go
@@ -34,6 +34,7 @@ var (
 	errNoSuchChannel                  = errors.New("No such channel")
 	errRenamePrivsNeeded              = errors.New("Only chanops can rename channels")
 	errSaslFail                       = errors.New("SASL failed")
+	errTooManyKeys                    = errors.New("Too many metadata keys")
 )
 
 // Socket Errors
diff --git a/irc/handlers.go b/irc/handlers.go
index 5ab121ee..fdd68973 100644
--- a/irc/handlers.go
+++ b/irc/handlers.go
@@ -1311,6 +1311,300 @@ func lusersHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *Re
 	return false
 }
 
+// METADATA * SUB <key>{ <key>}
+// METADATA * SUBS
+// METADATA * UNSUB <key>{ <key>}
+// METADATA <target> CLEAR
+// METADATA <target> GET <key>{ <key>}
+// METADATA <target> LIST
+// METADATA <target> SET <key> [<value>]
+// METADATA <target> SYNC
+func metadataHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	handler, exists := metadataSubcommands[strings.ToLower(msg.Params[1])]
+
+	if !exists {
+		rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.Nick(), "METADATA", client.t("Unknown subcommand"))
+		return false
+	}
+
+	return handler(server, client, msg, rb)
+}
+
+// METADATA <target> CLEAR
+func metadataClearHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	var mm *MetadataManager
+
+	targetString := msg.Params[0]
+	target, err := CasefoldChannel(targetString)
+	if err == nil {
+		channel := server.channels.Get(target)
+		if channel == nil {
+			rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			return false
+		}
+		if !channel.ClientIsAtLeast(client, modes.ChannelOperator) {
+			rb.Add(nil, server.name, ERR_CHANOPRIVSNEEDED, client.nick, targetString, client.t("You're not a channel operator"))
+			return false
+		}
+		mm = channel.metadata
+	} else {
+		target, err = CasefoldName(targetString)
+		user := server.clients.Get(target)
+		if err != nil || user == nil {
+			if len(target) > 0 {
+				rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			} else {
+				rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.Nick(), "METADATA", client.t("Unknown error"))
+			}
+			return false
+		}
+		if user != client {
+			rb.Add(nil, server.name, ERR_KEYNOPERMISSION, client.nick, target, "*", client.t("Permission denied"))
+			return false
+		}
+		mm = user.metadata
+	}
+
+	for _, key := range mm.Clear() {
+		rb.Add(nil, server.name, RPL_KEYVALUE, client.nick, target, key, "*")
+	}
+	rb.Add(nil, server.name, RPL_METADATAEND, client.nick, client.t("End of metadata"))
+
+	return false
+}
+
+// METADATA <target> GET <key>{ <key>}
+func metadataGetHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	if len(msg.Params) < 3 {
+		rb.Add(nil, server.name, ERR_NEEDMOREPARAMS, client.Nick(), msg.Command, client.t("Not enough parameters"))
+		return false
+	}
+
+	var mm *MetadataManager
+
+	targetString := msg.Params[0]
+	target, err := CasefoldChannel(targetString)
+	if err == nil {
+		channel := server.channels.Get(target)
+		if channel == nil {
+			rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			return false
+		}
+		if !channel.hasClient(client) {
+			rb.Add(nil, server.name, ERR_KEYNOPERMISSION, client.nick, target, client.t("You're not on that channel!"))
+			return false
+		}
+		mm = channel.metadata
+	} else {
+		target, err = CasefoldName(targetString)
+		user := server.clients.Get(target)
+		if err != nil || user == nil {
+			if len(target) > 0 {
+				rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			} else {
+				rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.Nick(), "METADATA", client.t("Unknown error"))
+			}
+			return false
+		}
+		mm = user.metadata
+	}
+
+	for i, key := range msg.Params {
+		// only process actual keys, skip target and (sub)command name
+		if 1 < i {
+			key = strings.TrimSpace(strings.ToLower(key))
+			if !metadataKeyValid(key) {
+				rb.Add(nil, server.name, ERR_KEYINVALID, client.nick, key)
+				continue
+			}
+			value, exists := mm.Get(key)
+			if !exists {
+				rb.Add(nil, server.name, ERR_NOMATCHINGKEY, client.nick, target, key, client.t("No matching key"))
+				continue
+			}
+
+			rb.Add(nil, server.name, RPL_KEYVALUE, client.nick, target, key, "*", value)
+		}
+	}
+	return false
+}
+
+// METADATA <target> LIST
+func metadataListHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	var mm *MetadataManager
+
+	targetString := msg.Params[0]
+	target, err := CasefoldChannel(targetString)
+	if err == nil {
+		channel := server.channels.Get(target)
+		if channel == nil {
+			rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			return false
+		}
+		if !channel.hasClient(client) {
+			rb.Add(nil, server.name, ERR_KEYNOPERMISSION, client.nick, target, client.t("You're not on that channel!"))
+			return false
+		}
+		mm = channel.metadata
+	} else {
+		target, err = CasefoldName(targetString)
+		user := server.clients.Get(target)
+		if err != nil || user == nil {
+			if len(target) > 0 {
+				rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			} else {
+				rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.Nick(), "METADATA", client.t("Unknown error"))
+			}
+			return false
+		}
+		mm = user.metadata
+	}
+
+	for key, value := range mm.List() {
+		rb.Add(nil, server.name, RPL_KEYVALUE, client.nick, target, key, "*", value)
+	}
+	rb.Add(nil, server.name, RPL_METADATAEND, client.nick, client.t("End of metadata"))
+
+	return false
+}
+
+// METADATA <target> SET <key> [<value>]
+func metadataSetHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	if len(msg.Params) < 3 {
+		rb.Add(nil, server.name, ERR_NEEDMOREPARAMS, client.Nick(), msg.Command, client.t("Not enough parameters"))
+		return false
+	}
+
+	// retrieve key/value
+	key := strings.TrimSpace(strings.ToLower(msg.Params[2]))
+	if !metadataKeyValid(key) {
+		rb.Add(nil, server.name, ERR_KEYINVALID, client.nick, key)
+		return false
+	}
+
+	var settingValue bool
+	var value string
+	if 3 < len(msg.Params) {
+		settingValue = true
+		value = msg.Params[3]
+	}
+
+	// work on target
+	targetString := msg.Params[0]
+	target, err := CasefoldChannel(targetString)
+	if err == nil {
+		channel := server.channels.Get(target)
+		if channel == nil {
+			rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			return false
+		}
+		if !channel.ClientIsAtLeast(client, modes.ChannelOperator) {
+			rb.Add(nil, server.name, ERR_CHANOPRIVSNEEDED, client.nick, targetString, client.t("You're not a channel operator"))
+			return false
+		}
+		if settingValue {
+			err := channel.metadata.Set(key, value, server.MetadataKeysLimit())
+			if err == errTooManyKeys {
+				rb.Add(nil, server.name, ERR_METADATALIMIT, client.nick, target, client.t("Metadata limit reached"))
+				return false
+			}
+		} else {
+			channel.metadata.Delete(key)
+		}
+	} else {
+		target, err = CasefoldName(targetString)
+		user := server.clients.Get(target)
+		if err != nil || user == nil {
+			if len(target) > 0 {
+				rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			} else {
+				rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.Nick(), "METADATA", client.t("Unknown error"))
+			}
+			return false
+		}
+		if user != client {
+			rb.Add(nil, server.name, ERR_KEYNOPERMISSION, client.nick, target, "*", client.t("Permission denied"))
+			return false
+		}
+		if settingValue {
+			err := user.metadata.Set(key, value, server.MetadataKeysLimit())
+			if err == errTooManyKeys {
+				rb.Add(nil, server.name, ERR_METADATALIMIT, client.nick, target, client.t("Metadata limit reached"))
+				return false
+			}
+		} else {
+			user.metadata.Delete(key)
+		}
+	}
+
+	if settingValue {
+		rb.Add(nil, server.name, RPL_KEYVALUE, client.nick, target, key, "*", value)
+	} else {
+		rb.Add(nil, server.name, RPL_KEYVALUE, client.nick, target, key, "*")
+	}
+	rb.Add(nil, server.name, RPL_METADATAEND, client.nick, client.t("End of metadata"))
+
+	return false
+}
+
+func metadataSubHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	client.Notice("METADATA SUB not yet implemented")
+	return false
+}
+
+func metadataSubsHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	client.Notice("METADATA SUBS not yet implemented")
+	return false
+}
+
+// METADATA <target> SYNC
+//TODO(dan): SYNC also returns e.g. metadata keys of friends in the given channel, etc.
+//Note:
+// One difference with list is that you can’t get a whole channel full of members metadata with it.
+// With sync you can, you get targets you didn’t explicitly request. It’s more of a trigger than a request.
+// And it’s mainly only useful for the delayed synchronisation function.
+func metadataSyncHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	var mm *MetadataManager
+
+	targetString := msg.Params[0]
+	target, err := CasefoldChannel(targetString)
+	if err == nil {
+		channel := server.channels.Get(target)
+		if channel == nil {
+			rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			return false
+		}
+		if !channel.hasClient(client) {
+			rb.Add(nil, server.name, ERR_KEYNOPERMISSION, client.nick, target, client.t("You're not on that channel!"))
+			return false
+		}
+		mm = channel.metadata
+	} else {
+		target, err = CasefoldName(targetString)
+		user := server.clients.Get(target)
+		if err != nil || user == nil {
+			if len(target) > 0 {
+				rb.Add(nil, server.name, ERR_TARGETINVALID, client.nick, target, client.t("Invalid metadata target"))
+			} else {
+				rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.Nick(), "METADATA", client.t("Unknown error"))
+			}
+			return false
+		}
+		mm = user.metadata
+	}
+
+	for key, value := range mm.List() {
+		rb.Add(nil, server.name, "METADATA", target, key, "*", value)
+	}
+
+	return false
+}
+
+func metadataUnsubHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	client.Notice("METADATA UNSUB not yet implemented")
+	return false
+}
+
 // MODE <target> [<modestring> [<mode arguments>...]]
 func modeHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
 	_, errChan := CasefoldChannel(msg.Params[0])
@@ -1448,7 +1742,7 @@ func monitorHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *R
 	handler, exists := monitorSubcommands[strings.ToLower(msg.Params[0])]
 
 	if !exists {
-		rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.Nick(), "MONITOR", msg.Params[0], client.t("Unknown subcommand"))
+		rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.Nick(), "MONITOR", client.t("Unknown subcommand"))
 		return false
 	}
 
diff --git a/irc/help.go b/irc/help.go
index 9c81e99b..ca80410d 100644
--- a/irc/help.go
+++ b/irc/help.go
@@ -269,6 +269,13 @@ channels). <elistcond>s modify how the channels are selected.`,
 Shows statistics about the size of the network. If <mask> is given, only
 returns stats for servers matching the given mask.  If <server> is given, the
 command is processed by that server.`,
+	},
+	"metadata": {
+		text: `METADATA <target> <subcommand> [<param>...]
+
+Sets, removes and displays metadata about clients and channels. For more
+specific information, see the spec here:
+https://github.com/jwheare/ircv3-specifications/blob/metadata/core/metadata-3.2.md`,
 	},
 	"mode": {
 		text: `MODE <target> [<modestring> [<mode arguments>...]]
diff --git a/irc/metadata.go b/irc/metadata.go
new file mode 100644
index 00000000..5c1740ef
--- /dev/null
+++ b/irc/metadata.go
@@ -0,0 +1,192 @@
+// Copyright (c) 2018 Daniel Oaks <daniel@danieloaks.net>
+// released under the MIT license
+
+package irc
+
+import (
+	"sync"
+
+	"github.com/goshuirc/irc-go/ircmsg"
+)
+
+var (
+	//TODO(dan): temporary hardcoded limits, make these configurable instead.
+	metadataKeysLimit = 20
+	metadataSubsLimit = 20
+)
+
+// MetadataKeysLimit returns how many metadata keys can be set on each client/channel.
+//TODO(dan): have this be configurable in the config file instead.
+func (server *Server) MetadataKeysLimit() int {
+	return metadataKeysLimit
+}
+
+// MetadataSubsLimit returns how many metadata keys can be subscribed to.
+//TODO(dan): have this be configurable in the config file instead.
+func (server *Server) MetadataSubsLimit() int {
+	return metadataSubsLimit
+}
+
+// MetadataManager manages metadata for a client or channel.
+type MetadataManager struct {
+	sync.RWMutex
+	// keyvals holds our values internally.
+	keyvals map[string]string
+}
+
+// NewMetadataManager returns a new MetadataManager.
+func NewMetadataManager() *MetadataManager {
+	var mm MetadataManager
+	mm.keyvals = make(map[string]string)
+	return &mm
+}
+
+// Clear deletes all keys, returning a list of the deleted keys.
+func (mm *MetadataManager) Clear() []string {
+	var keys []string
+
+	mm.Lock()
+	defer mm.Unlock()
+
+	for key := range mm.keyvals {
+		keys = append(keys, key)
+		delete(mm.keyvals, key)
+	}
+	return keys
+}
+
+// List returns all keys and values.
+func (mm *MetadataManager) List() map[string]string {
+	data := make(map[string]string)
+
+	mm.RLock()
+	defer mm.RUnlock()
+
+	for key, value := range mm.keyvals {
+		data[key] = value
+	}
+	return data
+}
+
+// Get returns the value of a single key.
+func (mm *MetadataManager) Get(key string) (string, bool) {
+	mm.RLock()
+	defer mm.RUnlock()
+
+	value, exists := mm.keyvals[key]
+	return value, exists
+}
+
+// Set sets the value of the given key. A limit of -1 means ignore any limits.
+func (mm *MetadataManager) Set(key, value string, limit int) error {
+	mm.Lock()
+	defer mm.Unlock()
+
+	_, currentlyExists := mm.keyvals[key]
+	if limit != -1 && !currentlyExists && limit < len(mm.keyvals)+1 {
+		return errTooManyKeys
+	}
+
+	mm.keyvals[key] = value
+
+	return nil
+}
+
+// Delete removes the given key.
+func (mm *MetadataManager) Delete(key string) {
+	mm.Lock()
+	defer mm.Unlock()
+
+	delete(mm.keyvals, key)
+}
+
+// MetadataSubsManager manages metadata key subscriptions.
+type MetadataSubsManager struct {
+	sync.RWMutex
+	// watchedKeys holds our list of watched (sub'd) keys.
+	watchedKeys map[string]bool
+}
+
+// NewMetadataSubsManager returns a new MetadataSubsManager.
+func NewMetadataSubsManager() *MetadataSubsManager {
+	var msm MetadataSubsManager
+	msm.watchedKeys = make(map[string]bool)
+	return &msm
+}
+
+// Sub subscribes to the given keys.
+func (msm *MetadataSubsManager) Sub(key ...string) {
+	msm.Lock()
+	defer msm.Unlock()
+
+	for _, k := range key {
+		msm.watchedKeys[k] = true
+	}
+}
+
+// Unsub ubsubscribes from the given keys.
+func (msm *MetadataSubsManager) Unsub(key ...string) {
+	msm.Lock()
+	defer msm.Unlock()
+
+	for _, k := range key {
+		delete(msm.watchedKeys, k)
+	}
+}
+
+// List returns a list of the currently-subbed keys.
+func (msm *MetadataSubsManager) List() []string {
+	var keys []string
+
+	msm.RLock()
+	defer msm.RUnlock()
+
+	for k := range msm.watchedKeys {
+		keys = append(keys, k)
+	}
+
+	return keys
+}
+
+var (
+	metadataValidChars = map[rune]bool{
+		'a': true, 'b': true, 'c': true, 'd': true, 'e': true, 'f': true, 'g': true,
+		'h': true, 'i': true, 'j': true, 'k': true, 'l': true, 'm': true, 'o': true,
+		'p': true, 'q': true, 'r': true, 's': true, 't': true, 'u': true, 'v': true,
+		'w': true, 'x': true, 'y': true, 'z': true, '0': true, '1': true, '2': true,
+		'3': true, '4': true, '5': true, '6': true, '7': true, '8': true, '9': true,
+		'_': true, '-': true, '.': true, ':': true,
+	}
+)
+
+// metadataKeyValid returns true if the given key is valid.
+func metadataKeyValid(key string) bool {
+	// key length
+	if len(key) < 1 {
+		return false
+	}
+	// invalid first character for a key
+	if key[0] == ':' {
+		return false
+	}
+	// name characters
+	for _, cha := range []rune(key) {
+		if metadataValidChars[rune(cha)] == false {
+			return false
+		}
+	}
+	return true
+}
+
+var (
+	metadataSubcommands = map[string]func(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool{
+		"clear": metadataClearHandler,
+		"get":   metadataGetHandler,
+		"list":  metadataListHandler,
+		"set":   metadataSetHandler,
+		"sub":   metadataSubHandler,
+		"subs":  metadataSubsHandler,
+		"sync":  metadataSyncHandler,
+		"unsub": metadataUnsubHandler,
+	}
+)
diff --git a/irc/numerics.go b/irc/numerics.go
index ec8e83cc..9996f880 100644
--- a/irc/numerics.go
+++ b/irc/numerics.go
@@ -173,6 +173,21 @@ const (
 	RPL_MONLIST                     = "732"
 	RPL_ENDOFMONLIST                = "733"
 	ERR_MONLISTFULL                 = "734"
+	RPL_WHOISKEYVALUE               = "760"
+	RPL_KEYVALUE                    = "761"
+	RPL_METADATAEND                 = "762"
+	ERR_METADATALIMIT               = "764"
+	ERR_TARGETINVALID               = "765"
+	ERR_NOMATCHINGKEY               = "766"
+	ERR_KEYINVALID                  = "767"
+	ERR_KEYNOTSET                   = "768"
+	ERR_KEYNOPERMISSION             = "769"
+	RPL_METADATASUBOK               = "770"
+	RPL_METADATAUNSUBOK             = "771"
+	RPL_METADATASUBS                = "772"
+	ERR_METADATATOOMANYSUBS         = "773"
+	ERR_METADATASYNCLATER           = "774"
+	ERR_METADATARATELIMIT           = "775"
 	RPL_LOGGEDIN                    = "900"
 	RPL_LOGGEDOUT                   = "901"
 	ERR_NICKLOCKED                  = "902"
diff --git a/irc/server.go b/irc/server.go
index e6a5570b..28e0b01b 100644
--- a/irc/server.go
+++ b/irc/server.go
@@ -51,7 +51,7 @@ var (
 
 	// SupportedCapabilities are the caps we advertise.
 	// MaxLine, SASL and STS are set during server startup.
-	SupportedCapabilities = caps.NewSet(caps.AccountTag, caps.AccountNotify, caps.AwayNotify, caps.Batch, caps.CapNotify, caps.ChgHost, caps.EchoMessage, caps.ExtendedJoin, caps.InviteNotify, caps.LabeledResponse, caps.Languages, caps.MessageTags, caps.MultiPrefix, caps.Rename, caps.Resume, caps.ServerTime, caps.UserhostInNames)
+	SupportedCapabilities = caps.NewSet(caps.AccountTag, caps.AccountNotify, caps.AwayNotify, caps.Batch, caps.CapNotify, caps.ChgHost, caps.EchoMessage, caps.ExtendedJoin, caps.InviteNotify, caps.LabeledResponse, caps.Languages, caps.MessageTags, caps.Metadata, caps.MultiPrefix, caps.Rename, caps.Resume, caps.ServerTime, caps.UserhostInNames)
 
 	// CapValues are the actual values we advertise to v3.2 clients.
 	// actual values are set during server startup.
@@ -835,6 +835,9 @@ func (server *Server) applyConfig(config *Config, initial bool) error {
 
 	server.languages = lm
 
+	// Metadata
+	CapValues.Set(caps.Metadata, "maxsub=10")
+
 	// SASL
 	oldAccountConfig := server.AccountConfig()
 	authPreviouslyEnabled := oldAccountConfig != nil && oldAccountConfig.AuthenticationEnabled