Why does a point release force recompile?

5.1 just dropped
I just converted all my projects to 5.0.3
now 5.1 drops
why doesn’t the new engine use the ddc?
my god.
I have to recompile thousands of shaders over a dozen projects
hours of time
why isn’t it using the ddc!

ahh.
its not so bad
most are loading fast
city sample is choking on 5.1 tho
and I like City Sample.
Will not compile for 5.1 only runs in 5.0.3