[pconf]

We don't use as much perl as we used to but the last upgrade issue was amavisd-new (a Spamassassin wrapper). Spamassassin has perl version issues every so often as well. NetDNS used to introduce new bugs about every 4th revision but seems to have been stable for the past couple of years. GNUmp3d and many audio libraries have non-perl revision-related, backwards-compatibility issues with some regularity.

[chromatic]

That makes sense. XS components (compiled code which uses the Perl API) don't have binary backwards compatibility between major Perl releases.

[pconf]

The audio library incompatibilities were API changes. Amavisd's issues are not binary either but do seem mostly socket related.