Versioning forms/models

gistfile1.txt

For instance, say I have an 'annual review' form for people. Last year 
they had to fill out training courses attended, this year they don't.
Next year the form changes completely but is still called an 'annual
review' as far as the business is concerned.  The forms can change 
pretty much any time - not just on a nice annual cycle (naturally).

There are also process/logic changes like one year a review has to be 
signed off by the line manager.  Next year it has to be also signed off 
by their unit head.  The year after there is an arbitration process 
introduced so if the person appeals the decision of $whoever was supposed 
to sign it off, which in turn changes the year after...

So a user will want to see a list of all annual reviews and expect to 
be able to click it and see the right form & data for that particular 
review irrespective of when it was made.

My current (horrible) system creates models & views like 
'AnnualReviewV20160825' views/annual_review/2016_08_25/show.blade.php 
which is pretty horrific.  It's like conditional spaghetti :-/ 

I keep seeing a better solution out of the corner of my eye, then it 
slides out of view the moment I turn my head...