How to install newer/testing version of a library?

[Chris Green]

Is it possible to install a newer/upcoming version of a library file
in Ubuntu?

I'm running xubuntu 21.10 on one of my systems and there's a bug in
PCRE which is causing me problems.

The bug is a new one, my older systems running PCRE version 10.36
don't have the problem, it's only version 10.37 that has the problem.

So I could either downgrade to PCRE 10.36 or upgrade to 10.38.

This affects three library packages:-

ii  libpcre2-16-0:amd64                   10.37-0ubuntu2                         amd64        New Perl Compatible Regular Expression Library - 16 bit runtime files
ii  libpcre2-32-0:amd64                   10.37-0ubuntu2                         amd64        New Perl Compatible Regular Expression Library - 32 bit runtime files
ii  libpcre2-8-0:amd64                    10.37-0ubuntu2                         amd64        New Perl Compatible Regular Expression Library- 8 bit runtime files

... and the bug manifests itself for me when using these from PHP in apache2. 
(presumably only one is being used by apache2 but I'm not really sure
which one it's using)

-- 
Chris Green