[GNC] Old-New user with an upgrade problem

[John Angelico]

Hi all.

I previously used GC 2.6.15 (more than 2 years ago) on an earlier Debian
(Jessie).

I'm now on Debian/buster and wish to resume, so checked out what I
could install, and found v3.4 available in my Debian packages.

But this won't install due to a dependency error with python-gnucash as per
this:
---
Some packages could not be installed. This may mean that you have requested
an impossible situation or if you are using the unstable distribution that
some required packages have not yet been created or been moved out of
Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 python-gnucash : Depends: gnucash (= 1:2.6.15-1) but 1:3.4-1+b10 is to be
installed
E: Broken packages
---
The next thing I tried was to upgrade the package on its own:
---
$ sudo apt upgrade python-gnucash
Reading package lists... Done
Building dependency tree
Reading state information... Done
python-gnucash is already the newest version (1:2.6.15-1).
python-gnucash set to manually installed.
---
Still no success.

How can I either:
a) upgrade python-gnucash to the correct level
or
b) find a way to fix up the dependency in GC 3.4
please?
-- 
Regards
John Angelico