1.12.X is newer than 1.8.X.
When in doubt, just use the Version module to make sure:
iex(1)> Version.compare("1.12.0", "1.8.2")
:gt
:gt means “greater”, e.g. 1.12.0 > 1.8.2 in this case.
And to address your original problem:
iex(2)> Version.match?("1.8.2", "~> 1.12.0")
false
