Upgrade MM 5.3.1 to latest version fails

Troubleshooting
52

Hello, XxLilBoPeepsxX,
I have done it now again :upside_down_face:. First my upgrade procedure, than the result:

get MM version 5.9.8

mkdir /opt/tmp
cd /opt/tmp
wget https://releases.mattermost.com/5.9.8/mattermost-5.9.8-linux-amd64.tar.gz
tar -xzf mattermost-5.9.8-linux-amd64.tar.gz

cd /opt

backup current MM state

systemctl stop mattermost
mysqldump -u root -p mattermost > mm.sql
rsync -a mattermost mm.bak
rsync -a mattermost.data mm.data.bak

prepare new MM version

rsync -a mattermost/config/ tmp/mattermost/config/
rsync -au mattermost/plugins/ tmp/mattermost/plugins
rsync -au mattermost/client/plugins/ tmp/mattermost/client/plugins

change MM installations

mv mattermost old.mattermost
mv tmp/mattermost mattermost
chown -R mattermost:mattermost mattermost