I agree 100% with this. I once had a project that was versions behind the current platform. I couldn't upgrade because the tools to upgrade were gone and I was constantly having to fire off questions to the lead contributor who was around for that version in order to get stuff done.
Upgrade as soon as a stable build of the major version is released and pay the engineering costs or be left with something worse than legacy.
Upgrade as soon as a stable build of the major version is released and pay the engineering costs or be left with something worse than legacy.