There seem to be several things that were valid in Embperl 1.x that are no longer supported in Embperl 2.x. As an example:
[+ +]blocks must now contain a valid Perl expression. Embperl 1.x allows you to put multiple statements into such a block. For performance reasons this is not possible anymore.
Given a very large Embperl 1.x codebase, is there an automated way to scan the .epl files and discover the incompatibilities? I don't care about implementation - anything from some special flag in Embperl 2.0 to some plugin for Perl::Critic is fine.
As long as it's not Mark 1 eyeball or "switch to Embperl2 and see what breaks" :)
This forum talk seem to be just what you need Migrating from embperl 1.3 to Embperl 2
The script presented there claims not only to detect the incompatibilities, but also correcting them.