Just in case anyone reads this and is trying to upgrade Galaxy from pre-Galaxy 20 versions (in my case 16) with older pre-Ubuntu 20 versions (in my case 14) )— it is not possible since Galaxy and Ubuntu are co-dependent through this time period. Ubuntu is very difficult/impossible to upgrade successfully. Similarly Galaxy’s requirements (mainly Python) change greatly through this period. I ended up copying raw data off my Galaxy installation; wiping the server; installing Ubuntu 20; and then the Ansible version of Galaxy 21 – the latter based on these tutorials.
New install of Galaxy
Add on Ansible – install Proftpd
Ansible does make it easy - although there are a couple of errors and poorly explained sections in the tutorials that required some headscratching and tweaking.
Cross-posted topic: toolshed not working anymore with old galaxy?