Mods for Factorio 0.16 couldn't run with Factorio 0.17, mods for 0.17 couldn't run with 0.18, and mods for 1.0 won't run with 1.1 -- but mods for Factorio 0.18 can be used with Factorio 1.0. (There were some mod-breaking changes like the cutscene at the start of a new game, but these changes don't affect all mods, and most affected mods have been fixed and will run with Factorio 1.0 even if they are listed as 0.18 mods.)
TLDR: 0.56 should work with both Factorio 0.18 and 1.0.
