diff --git a/package.json b/package.json
index ee53999..3fe980e 100644
--- a/package.json
+++ b/package.json
@@ -9,8 +9,9 @@
   "author": "David A Roberts",
   "license": "MIT",
   "dependencies": {
-    "parent-require": "^1.0.0",
-    "matrix-js-sdk": "*"
+    "matrix-js-sdk": "*",
+    "node-localstorage": "^1.3.0",
+    "parent-require": "^1.0.0"
   },
   "peerDependencies": {
     "hubot": ">=2.0"
diff --git a/src/matrix.coffee b/src/matrix.coffee
index 278a90e..fb22ef0 100644
--- a/src/matrix.coffee
+++ b/src/matrix.coffee
@@ -7,6 +7,10 @@ catch
 sdk = require 'matrix-js-sdk'
 request = require 'request'
 
+unless localStorage?
+  {LocalStorage} = require('node-localstorage')
+  localStorage = new LocalStorage('./hubot-matrix.localStorage')
+
 class Matrix extends Adapter
   constructor: ->
     super
@@ -18,10 +22,13 @@ class Matrix extends Adapter
       if /^(f|ht)tps?:\/\//i.test(str)
         @sendImage envelope, str
       else
-        @client.sendMessage envelope.room, {
-          msgtype: "m.notice",
-          body: str
-        }
+        @client.sendNotice(envelope.room, str).catch (err) =>
+          if err.name == 'UnknownDeviceError'
+            for stranger, devices of err.devices
+              for device, _ of devices
+                @robot.logger.info "Acknowledging #{stranger}'s device #{device}"
+                @client.setDeviceKnown(stranger, device)
+            @client.sendNotice(envelope.room, str)
 
   emote: (envelope, strings...) ->
     for str in strings
@@ -60,11 +67,14 @@ class Matrix extends Adapter
             return
         @user_id = data.user_id
         @access_token = data.access_token
-        @robot.logger.info "Logged in #{@user_id}"
+        @device_id = data.device_id
+        @robot.logger.info "Logged in #{@user_id} on device #{@device_id}"
         @client = sdk.createClient
             baseUrl: process.env.HUBOT_MATRIX_HOST_SERVER || 'https://matrix.org'
             accessToken: @access_token
             userId: @user_id
+            deviceId: @device_id
+            sessionStore: new sdk.WebStorageSessionStore(localStorage)
         @client.on 'sync', (state, prevState, data) =>
             switch state
               when "PREPARED"