You can find the release notes for 0.1.12 here: https://github.com/rbuckton/reflect-metadata/releases/tag/v0.1.12

There should not have been any major breaking changes in that release, though it did introduce a mechanism to avoid overwriting an existing copy of reflect-metadata that may have been loaded from a different path by another package. At the time, that mechanism meant that an older version of reflect-metadata would always take precedence over a newer version. I've changed the mechanism as of reflect-metadata@0.2.1 so that multiple versions can be loaded into memory at the same time, so you may want to see if 0.2.1 improves the situation for you.