Issue BAM-19620 created the ability to allow build plans to have different steps for repository stored specs.  This is great - as our system changes and new components are introduced, old ones are removed, the build can update as it goes.

However, as noted in the documentation, "Branch divergence is not available for deployment projects. Bamboo ignores any Bamboo Specs on deployment projects in divergent branches."

So, as we go along, we update BuildSpecs.java in the relevant branches and things are fine.  Need to change a deployment?  Now you instead have to jump over to the master branch and make changes there.  Your new branch/version has different requirements / steps than the old one?  Sorry, you'll have to make your deployment convoluted in order to handle all possible combinations at once.

The exact same reasons that made it a good idea for build plans should make it a good idea for deployment plans as well.