MyBB upgrade error from 1.6.16 to 1.8.3

I use MyBB forum application in my private project. Current version is 1.6.16, it is too old so I tried to upgrade to the latest 1.8.3.

1. Download the latest MyBB package file.

   $ wget http://resources.mybb.com/downloads/mybb_1803.zip
   

2. Extract the zip file and copy to existing directory.

   $ cd ./downloaded_directory
   $ unzip mybb_1803.zip
   $ rsync -av ./Upload/ /existsing/mybb/directory/
   

3. Open the url in browser for upgrade.

   http://my-personal-project-hostname/install/upgrade.php
   

Then I got following error.

MyBB has experienced an internal SQL error and cannot continue.

SQL Error: 1366 - Incorrect string value: ‘\x94W’ for column ‘ip’ at row 1 Query: REPLACE INTO mybb_sessions SET `uid`=’1’,`sid`=’577294dda4c2090968dbbe2f2951183d’, `time`=’1419722669’,`ip`=X’caa29457’,`location`=’/install/upgrade.php?’, `useragent`=’Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.’,`location1`=’0’,`location2`=’0’, `nopermission`=’0’

I don’t know how to fix this so the version is still 1.6.16.