As you can see, pgjdbc is rather conservative, and there's a good reason for that.
So I do not expect lots of major version changes.
On the other hand, PG might increment major version each year, so I find pgjdbc 13.0 vs pg 13.0 version clash quite real.
Even if we arbitrary advance major version once a year, PG 13.0 would clash with pgjdbc 13.0.
>
There should be no problem since the version is greater than current one, 13 > 9
(or 42 > 9)
so packaging should be no problem...
In theory, there's no difference between theory and practice. In practice, there is.
For instance, some packaging scripts might easily use "9.4" part as a string literal since pgjdbc had "9.4.x" versions for quite a while.
On the other hand, I think 42.0.0 should not create showstopper problems for packagers.
Vladimir