vyperversions.txt

0.3.0 rearranged internal function params & constructor params
0.3.0 removed spaces after strings (affects both memory and storage)

Storage rearranged in 0.2.13

Source maps added in: 0.1.0-beta.7
Solidity-style source maps added in: 0.1.0-beta.12
JSON interface added in: 0.1.0-beta.13
ASTs added in: 0.1.0-beta.13
outputSelection moved into settings: 0.1.0-beta.15
userdoc and devdoc added in: 0.1.0-beta.17
vyper --standard-json added in: 0.2.5

Note: There are still no source maps for constructors.
Note: I don't know how ASTs have changed over time; they appear to have changed
a fair bit.

external function parameters changed in 0.1.0-beta.11?
memory handling changed in 0.2.7??  Nothing I care about seems affected

I can't get anything nontrivial to compile on 0.1.0b13 or earlier...
and before 0.1.0-beta.12 we don't have ASTs anyway so who cares about external
function parameters :P