Technology

They migrated from an OS and MySQL version receiving no updates since at least 2 years to MySQL 8.0 which will stop getting updates in 4 days.

I agree that it was an odd choice, as well as the OS. Going to Alma 9 when Alma 10 had already been out for some time. Would think if they wanted the long term updates they would have gone to 10 to get the most out of it. If they went from 8 to 9, sure, some people like staying in the area where RedHat got bored and won't mess with it anymore, but 7 to 9 suggests they didn't do timely upgrades before.

Also every service is running without any containerization and there is a single database for everything

Well, he said explicitly they have 30 databases, though I suppose you meant a single mysql instance. I will say I won't judge one way or another about containerization, as I've seen about as much amateur hour containerization to not immediately judge one way or another on that.

it all runs on a single host

Yeah, that seems pretty dire given his stated usage scenario, and it seems very explicit that their entire internet facing world is that single host...

backup strategy or disk encryption

It was a post narrowly discussing migration, so I don't expect a full inventory of everything they do, so backup strategy and disk encryption and all sorts of other things may be omitted as having nothing to do with the core thing. I guess the most red flag on this front is he explicitly mentions the old setup having "backups enabled" and new setup having "RAID1", which does make me wonder if they think RAID1 is a credible answer for "backup".

Also not a single word about infrastructure as code

Again, not necessarily in-scope for this document, so not sure if I'm going to judge on this one. I routinely take material expressed in terms of an ansible play and "generic it out" for general consumption when discussing with people outside my organization.

The whole stuff is hosted in Germany for a Turkish software company

I'll confess to not liking it being in a single site, however to the extent they select a single site, Germany might make sense because:

Several live mobile apps serving hundreds of thousands of users

Their userbase may be better connected to Germany than Turkey, and the user latency matters more.

My biggest concerns would be mitigated if they said that the German hosted server is their off-prem solution but it is also hosted on-prem giving them multiple sites, but I think that's a bit much to imagine given the process described. The described migration process wouldn't make sense in that scenario.