if you see some infos about missing indexes or colums in your cloud after a update like :
The database is missing some indexes. Due to the fact that adding indexes on big tables could take some time they were not added automatically. By running "occ db:add-missing-indices" those missing indexes could be added manually while the instance keeps running. Once the indexes are added queries to those tables are usually much faster.
Some columns in the database are missing a conversion to big int. Due to the fact that changing column types on big tables could take some time they were not changed automatically. By running 'occ db:convert-filecache-bigint' those pending changes could be applied manually. This operation needs to be made while the instance is offline. For further details read the documentation page about this.
then you can just use the OCC TOOL https://billing.owncube.com/knowledgebase/46/How-to-use-occ-commands-without-SSH-access.html to run the required commands.