Hi. I post this topic to inform members who are experiencing the next issue in the 4.4.x version update.
The new version requires php version greater than or equal to 7.1, but recommended version 7.2.
This change to the php version can be made from your host's panel.
If you are experiencing the problem with error 500 (server does not respond) or error 503 (the server is currently busy) I suggest you change the php settings in the following way.
You will have to uncheck the box with "mysqli" and check the box with "nd-mysqli" because the version 7.1 above uses a new mysqli database structure.
I hope you can use this little "tutorial" for those who need and address this problem. I wish you a wonderful day.
Or you can backup entire your site, and update and watch what problems will be with this plugins, if any plugin have trouble, you can restore to previous backup.