Dependency freeze and optional dependencies

[Albert Astals Cid]

Should we allow new features that require optionally a new version of an 
existing dependency?

e.g. Okular depends on libtsd 0.1 and now i want to add a feature that 
optionally depends on libtsd 0.2, but if you have libtsd 0.1 it's all fine 
(i.e. it compiles but you don't get the new feature).

Does that count as breaking the dependency freeze?

Cheers,
  Albert