So, how much trouble would an upgrade be? I installed 5.22.0 on my laptop (OpenSUSE 13.2/64) and on my home PC (OpenSUSE 13.1/64).

Than I ran my (perl)script that will use CPAN to install all releases/modules that were installed in the previous installed active perl version. Having run that unattended with the use of cpanprefs, several hours later, the result is:

PC
   924 m5200
   843 m5220  91.2%
  9361 x5200
  9008 x5220  96.2%

Laptop
   978 m5200
  1129 m5201
  1121 m5202
  1050 m5220  93.7%
  9865 x5200
 10638 x5201
  9775 x5202
  9466 x5220  96.8%
[download]

To explain: the m52* lines show the number of distributions installed. The x52* lines show the number of modules (.pm files) installed.

Some modules do not install unattended, and I will spend the next few days to check why. There are of course some known reasons:

• it needs interaction like a mouseclick (X11, pTk, Wx)
• a mismatch in what is written in perllocal.pod and what CPAN knows the module as, like App::ack
• a module/release was deprecated or replaced, so that it cannot be installed on newer perl anymore, like Archive::Tar
• the most recent version was already installed by installing 5.22.0, so it does not appear in perllocal.pod
• it needs a special environment, like DBD::Oracle, DBD::Pg, and DBD::mysql
• the module tests a url that is not active (temporary or permanent)
• a required module failed. currently POE fails, which causes all modules that depend on it to fail
• the module is known to fail, and work is in progress to resolve that, like Devel::Cover
• a combination of the two reasons above, like Lexical::Var
• modules are not available on CPAN (anymore) (DarkPAN/BackPAN), like my company stuff
• modules that are not yet on CPAN :) (I have some pre-alpha stuff I test for friends that is installed. that obviously needs some extra actions)
• the testsuite fails on bad designed test when -Duselongdouble was used to build perl (more digits after the radix), like PerlMagick: Expected (0.454545), Got (0.454544999999999977)
• ...

All of those are reasons why the two states will never match 100%. Overall I think I can draw the conclusion that the upgrade went relatively smooth!

88 dists to check for my PC, and just 35 on my laptop.

For all modules I can find a reason for breakage under 5.22.0 that have not yet been reported, I'll file a ticket