Why is Python so picky in 2.25 - help needed?????

Can someone PLEASE tell me why Python has changed so much in Ver2.25 and why just about nothing Python works!!!.
I am a comparative newbie to Python but surely if I make a Python programme in 2.23 is should be close to running in 2.25.
It seems to be picky little things like say

mat = Blender.Material.Get(‘Halo’) works in 2.23
but I think the - Get - has to be changed to - get - in 2.25.

Is there a list of these silly changes out there?
It would be a great help to us struggling newbies as I would prefer to just learn ONE version of Blender Python - that is Ver 2.25.

Gripe over but help would be appreciated.