11 -> 12 upgrade on Debian Ubuntu

I am in the middle of a project, and it looks like version 12 is now what
the Debian/Ubuntu package managers want to update to. 

I of course, will do this first on a test machine, not the "production", or
"develop,met" machines, but I thought i would solicit the group wisdom on
this.

Are there any things I should watch out for here? Will my data be preserved
during this upgrade? We are just beginning to put real data in the
"production" instance, and just yesterday, I set up a script to do backups
using pg_basebackup. BTW this is the 1st time I have sued this, having
used pg_dump in the past. Database is fairly small with just one
tablespace if that matters.

Thanks for anyone's input.

-- 
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
                        -- Benjamin Franklin