Add string.

app/src/main/res/values/strings.xml

@@ -20,6 +20,7 @@
     <string name="msg_new_to_rocket_chat">New to Rocket Chat? <font color='#FF1976D2'>Sign up</font></string>
     <string name="msg_new_user_agreement">By proceeding you are agreeing to our\n<font color='#FF1976D2'>Terms of Service</font> and <font color='#FF1976D2'>Privacy Policy</font></string>
     <string name="msg_2fa_code">2FA Code</string>
+    <string name="msg_more_than_ninety_nine_unread_messages" translatable="false">99+</string>
     <string name="msg_content_description_log_in_using_facebook">Login using Facebook</string>
     <string name="msg_content_description_log_in_using_github">Login using Github</string>
     <string name="msg_content_description_log_in_using_google">Login using Google</string>