diff --git a/.gitignore b/.gitignore
index 66bc8edb..e15440d3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 matterircd
 matterircd.toml
+matterircd-lastsaved.db
diff --git a/matterircd.toml.example b/matterircd.toml.example
index 13febba8..45a1377f 100644
--- a/matterircd.toml.example
+++ b/matterircd.toml.example
@@ -134,6 +134,14 @@ SuffixContext = false
 #in your mattermost "word that trigger mentions" notifications.
 ShowMentions = false
 
+# Path to file to store last viewed information. This is useful for replying only
+# the messages missed.
+LastViewedSaveFile = "matterircd-lastsaved.db"
+# Interval for how often to save last viewed information.
+LastViewedSaveInterval = "5m"
+# Consider saved last view information stale if last saved older than this time
+LastViewedStaleDuration = "30d"
+
 #############################
 ##### SLACK EXAMPLE #########
 #############################
diff --git a/mm-go-irckit/server_commands.go b/mm-go-irckit/server_commands.go
index e6b79ab2..da9d6d77 100644
--- a/mm-go-irckit/server_commands.go
+++ b/mm-go-irckit/server_commands.go
@@ -389,8 +389,8 @@ func CmdPrivMsg(s Server, u *User, msg *irc.Message) error {
 
 		u.msgLastMutex.Lock()
 		defer u.msgLastMutex.Unlock()
-
 		u.msgLast[ch.ID()] = [2]string{msgID, ""}
+		u.saveLastViewedAt(ch.ID())
 
 		if u.v.GetBool(u.br.Protocol()+".prefixcontext") || u.v.GetBool(u.br.Protocol()+".suffixcontext") {
 			u.prefixContext(ch.ID(), msgID, "", "")
@@ -426,6 +426,7 @@ func CmdPrivMsg(s Server, u *User, msg *irc.Message) error {
 			u.msgLastMutex.Lock()
 			defer u.msgLastMutex.Unlock()
 			u.msgLast[toUser.User] = [2]string{msgID, ""}
+			u.saveLastViewedAt(toUser.User)
 
 			if u.v.GetBool(u.br.Protocol()+".prefixcontext") || u.v.GetBool(u.br.Protocol()+".suffixcontext") {
 				u.prefixContext(toUser.User, msgID, "", "")
@@ -512,6 +513,8 @@ func parseModifyMsg(u *User, msg *irc.Message, channelID string) bool {
 			return false
 		}
 		u.MsgSpoofUser(u, u.br.Protocol(), "msg: "+text+" could not be modified: "+err.Error())
+	} else {
+		u.saveLastViewedAt(channelID)
 	}
 
 	return true
@@ -592,8 +595,8 @@ func threadMsgChannel(u *User, msg *irc.Message, channelID string) bool {
 
 	u.msgLastMutex.Lock()
 	defer u.msgLastMutex.Unlock()
-
 	u.msgLast[channelID] = [2]string{msgID, threadID}
+	u.saveLastViewedAt(channelID)
 
 	if u.v.GetBool(u.br.Protocol()+".prefixcontext") || u.v.GetBool(u.br.Protocol()+".suffixcontext") {
 		u.prefixContext(channelID, msgID, "", "")
@@ -616,8 +619,8 @@ func threadMsgUser(u *User, msg *irc.Message, toUser string) bool {
 
 	u.msgLastMutex.Lock()
 	defer u.msgLastMutex.Unlock()
-
 	u.msgLast[toUser] = [2]string{msgID, threadID}
+	u.saveLastViewedAt(toUser)
 
 	if u.v.GetBool(u.br.Protocol()+".prefixcontext") || u.v.GetBool(u.br.Protocol()+".suffixcontext") {
 		u.prefixContext(toUser, msgID, "", "")
diff --git a/mm-go-irckit/userbridge.go b/mm-go-irckit/userbridge.go
index 2a202a42..b035e312 100644
--- a/mm-go-irckit/userbridge.go
+++ b/mm-go-irckit/userbridge.go
@@ -1,13 +1,17 @@
 package irckit
 
 import (
+	"errors"
 	"fmt"
 	"math/rand"
 	"net"
+	"os"
 	"strings"
 	"sync"
 	"time"
 
+	"encoding/gob"
+
 	"github.com/42wim/matterircd/bridge"
 	"github.com/42wim/matterircd/bridge/mattermost"
 	"github.com/42wim/matterircd/bridge/slack"
@@ -19,19 +23,25 @@ import (
 )
 
 type UserBridge struct {
-	Srv                Server
-	Credentials        bridge.Credentials
-	br                 bridge.Bridger            //nolint:structcheck
-	inprogress         bool                      //nolint:structcheck
-	lastViewedAt       map[string]int64          //nolint:structcheck
-	lastViewedAtMutex  sync.RWMutex              //nolint:structcheck
-	msgCounter         map[string]int            //nolint:structcheck
-	msgLast            map[string][2]string      //nolint:structcheck
-	msgLastMutex       sync.RWMutex              //nolint:structcheck
-	msgMap             map[string]map[string]int //nolint:structcheck
-	msgMapMutex        sync.RWMutex              //nolint:structcheck
-	updateCounter      map[string]time.Time      //nolint:structcheck
-	updateCounterMutex sync.Mutex                //nolint:structcheck
+	Srv         Server
+	Credentials bridge.Credentials
+	br          bridge.Bridger //nolint:structcheck
+	inprogress  bool           //nolint:structcheck
+
+	lastViewedAtMutex sync.RWMutex     //nolint:structcheck
+	lastViewedAt      map[string]int64 //nolint:structcheck
+
+	lastViewedAtSaved int64          //nolint:structcheck
+	msgCounter        map[string]int //nolint:structcheck
+
+	msgLastMutex sync.RWMutex         //nolint:structcheck
+	msgLast      map[string][2]string //nolint:structcheck
+
+	msgMapMutex sync.RWMutex              //nolint:structcheck
+	msgMap      map[string]map[string]int //nolint:structcheck
+
+	updateCounterMutex sync.Mutex           //nolint:structcheck
+	updateCounter      map[string]time.Time //nolint:structcheck
 }
 
 func NewUserBridge(c net.Conn, srv Server, cfg *viper.Viper) *User {
@@ -43,7 +53,7 @@ func NewUserBridge(c net.Conn, srv Server, cfg *viper.Viper) *User {
 
 	u.Srv = srv
 	u.v = cfg
-	u.lastViewedAt = make(map[string]int64)
+	u.lastViewedAt = u.loadLastViewedAt()
 	u.msgLast = make(map[string][2]string)
 	u.msgMap = make(map[string]map[string]int)
 	u.msgCounter = make(map[string]int)
@@ -150,9 +160,7 @@ func (u *User) handleDirectMessageEvent(event *bridge.DirectMessageEvent) {
 	if !u.v.GetBool(u.br.Protocol() + ".disableautoview") {
 		u.updateLastViewed(event.ChannelID)
 	}
-	u.lastViewedAtMutex.Lock()
-	defer u.lastViewedAtMutex.Unlock()
-	u.lastViewedAt[event.ChannelID] = model.GetMillis()
+	u.saveLastViewedAt(event.ChannelID)
 }
 
 func (u *User) handleChannelAddEvent(event *bridge.ChannelAddEvent) {
@@ -176,9 +184,7 @@ func (u *User) handleChannelAddEvent(event *bridge.ChannelAddEvent) {
 	if !u.v.GetBool(u.br.Protocol() + ".disableautoview") {
 		u.updateLastViewed(event.ChannelID)
 	}
-	u.lastViewedAtMutex.Lock()
-	defer u.lastViewedAtMutex.Unlock()
-	u.lastViewedAt[event.ChannelID] = model.GetMillis()
+	u.saveLastViewedAt(event.ChannelID)
 }
 
 func (u *User) handleChannelRemoveEvent(event *bridge.ChannelRemoveEvent) {
@@ -198,6 +204,7 @@ func (u *User) handleChannelRemoveEvent(event *bridge.ChannelRemoveEvent) {
 			ch.SpoofMessage("system", "removed "+removed.Nick+" from the channel by "+event.Remover.Nick)
 		}
 	}
+	u.saveLastViewedAt(event.ChannelID)
 }
 
 func (u *User) getMessageChannel(channelID, channelType string, sender *bridge.UserInfo) Channel {
@@ -284,9 +291,7 @@ func (u *User) handleChannelMessageEvent(event *bridge.ChannelMessageEvent) {
 	if !u.v.GetBool(u.br.Protocol() + ".disableautoview") {
 		u.updateLastViewed(event.ChannelID)
 	}
-	u.lastViewedAtMutex.Lock()
-	defer u.lastViewedAtMutex.Unlock()
-	u.lastViewedAt[event.ChannelID] = model.GetMillis()
+	u.saveLastViewedAt(event.ChannelID)
 }
 
 func (u *User) handleFileEvent(event *bridge.FileEvent) {
@@ -384,6 +389,7 @@ func (u *User) handleReactionEvent(event interface{}) {
 		}
 
 		u.handleDirectMessageEvent(e)
+		u.saveLastViewedAt(channelID)
 
 		return
 	}
@@ -399,6 +405,7 @@ func (u *User) handleReactionEvent(event interface{}) {
 	}
 
 	u.handleChannelMessageEvent(e)
+	u.saveLastViewedAt(channelID)
 }
 
 func (u *User) CreateUserFromInfo(info *bridge.UserInfo) *User {
@@ -626,12 +633,12 @@ func (u *User) addUserToChannelWorker(channels <-chan *bridge.ChannelInfo, throt
 			}
 		}
 
-		if !u.v.GetBool(u.br.Protocol() + ".disableautoview") {
-			u.updateLastViewed(brchannel.ID)
+		if len(mmPostList.Order) > 0 {
+			if !u.v.GetBool(u.br.Protocol() + ".disableautoview") {
+				u.updateLastViewed(brchannel.ID)
+			}
+			u.saveLastViewedAt(brchannel.ID)
 		}
-		u.lastViewedAtMutex.Lock()
-		u.lastViewedAt[brchannel.ID] = model.GetMillis()
-		u.lastViewedAtMutex.Unlock()
 	}
 }
 
@@ -885,3 +892,129 @@ func (u *User) updateLastViewed(channelID string) {
 		u.br.UpdateLastViewed(channelID)
 	}()
 }
+
+func (u *User) loadLastViewedAt() map[string]int64 {
+	statePath := u.v.GetString("mattermost.lastviewedsavefile")
+	if statePath == "" {
+		return make(map[string]int64)
+	}
+
+	staleDuration := u.v.GetString("mattermost.lastviewedstaleduration")
+	lastViewedAt, err := loadLastViewedAtStateFile(statePath, staleDuration)
+	if err != nil {
+		logger.Warning("Unable to load saved lastViewedAt, using empty values: ", err)
+		return make(map[string]int64)
+	}
+
+	logger.Info("Loaded lastViewedAt from ", time.Unix(lastViewedAt["__LastViewedStateSavedTime__"]/1000, 0))
+	u.lastViewedAtSaved = model.GetMillis()
+
+	return lastViewedAt
+}
+
+const defaultSaveInterval = int64((5 * time.Minute) / time.Millisecond)
+
+func (u *User) saveLastViewedAt(channelID string) {
+	u.lastViewedAtMutex.Lock()
+	defer u.lastViewedAtMutex.Unlock()
+	if channelID != "" {
+		u.lastViewedAt[channelID] = model.GetMillis()
+	}
+
+	statePath := u.v.GetString(u.br.Protocol() + ".lastviewedsavefile")
+	if statePath == "" {
+		return
+	}
+
+	// We only want to save or dump out saved lastViewedAt on new
+	// messages after X time.
+	var saveInterval int64
+	val, err := time.ParseDuration(u.v.GetString(u.br.Protocol() + ".lastviewedsaveinterval"))
+	if err != nil {
+		saveInterval = defaultSaveInterval
+	} else {
+		saveInterval = val.Milliseconds()
+	}
+	if u.lastViewedAtSaved < (model.GetMillis() - saveInterval) {
+		saveLastViewedAtStateFile(statePath, u.lastViewedAt)
+		u.lastViewedAtSaved = model.GetMillis()
+	}
+}
+
+const lastViewedStateFormat = int64(1)
+
+func saveLastViewedAtStateFile(statePath string, lastViewedAt map[string]int64) error {
+	f, err := os.Create(statePath)
+	if err != nil {
+		logger.Debug("Unable to save lastViewedAt: ", err)
+		return err
+	}
+	defer f.Close()
+
+	currentTime := model.GetMillis()
+
+	lastViewedAt["__LastViewedStateFormat__"] = lastViewedStateFormat
+	if _, ok := lastViewedAt["__LastViewedStateCreateTime__"]; !ok {
+		lastViewedAt["__LastViewedStateCreateTime__"] = currentTime
+	}
+	lastViewedAt["__LastViewedStateSavedTime__"] = currentTime
+	// Simple checksum
+	lastViewedAt["__LastViewedStateChecksum__"] = lastViewedAt["__LastViewedStateCreateTime__"] ^ currentTime
+
+	logger.Debug("Saving lastViewedAt")
+
+	if err := gob.NewEncoder(f).Encode(lastViewedAt); err != nil {
+		return fmt.Errorf("gob encoding failed: %s", err)
+	}
+
+	return nil
+}
+
+const defaultStaleDuration = int64((30 * 24 * time.Hour) / time.Millisecond)
+
+func loadLastViewedAtStateFile(statePath string, staleDuration string) (map[string]int64, error) {
+	f, err := os.Open(statePath)
+	if err != nil {
+		logger.Debug("Unable to load lastViewedAt: ", err)
+		return nil, err
+	}
+	defer f.Close()
+
+	var lastViewedAt map[string]int64
+	err = gob.NewDecoder(f).Decode(&lastViewedAt)
+	if err != nil {
+		logger.Debug("Unable to load lastViewedAt: ", err)
+		return nil, err
+	}
+
+	if lastViewedAt["__LastViewedStateFormat__"] != lastViewedStateFormat {
+		logger.Debug("State format version mismatch: ", lastViewedAt["__LastViewedStateFormat__"], " vs. ", lastViewedStateFormat)
+		return nil, errors.New("version mismatch")
+	}
+	checksum := lastViewedAt["__LastViewedStateChecksum__"]
+	createtime := lastViewedAt["__LastViewedStateCreateTime__"]
+	savedtime := lastViewedAt["__LastViewedStateSavedTime__"]
+	if createtime^savedtime != checksum {
+		logger.Debug("Checksum mismatch: (saved checksum, state file creation, last saved time)", checksum, createtime, savedtime)
+		return nil, errors.New("checksum mismatch")
+	}
+
+	currentTime := model.GetMillis()
+
+	// Check if stale, time last saved older than defined
+	var stale int64
+	val, err := time.ParseDuration(staleDuration)
+	if err != nil {
+		stale = defaultStaleDuration
+	} else {
+		stale = val.Milliseconds()
+	}
+
+	lastSaved, ok := lastViewedAt["__LastViewedStateSavedTime__"]
+	if !ok || (lastSaved > 0 && lastSaved < currentTime-stale) {
+		logger.Debug("File stale? Last saved too old: ", time.Unix(lastViewedAt["__LastViewedStateSavedTime__"]/1000, 0))
+		return nil, errors.New("stale lastViewedAt state file")
+	}
+
+	return lastViewedAt, nil
+}