It can go either way depending on context. The first couple versions
of Pyramid needed it because major API changes were being made between
development versions, so it was necessary to tie to the version with
the right API in order to develop your application. Some other
projects have long beta periods and there's not as much distinction
between betas and final, so the betas get used in applications. I
guess this mostly happens with small libraries like WebHelpers and
Routes, where most changes are adding a little incremental feature.
With Pyramid not undergoing major structural changes now, it would be
fine to say "added in 1.4", and people can look at the Changelog if
they want to know the specific beta.