How to upgrade from 2.1.6

I logged in after few months and I cant see upgrade link anymore…nor the version of my mautic…
Can I just upgrade it via WEB, I am on shared hosting…and I want to move to local dev with composer…
but 2.1.6. is not supported by composer I think

First of all take the necessary precautions. (Backup files and DB)
You should try to get SSH access to your server and perform a command line update.