The old flexsim-module-sdk repository is no longer accessible at https://bitbucket.org/flexsim/flexsim-module-sdk/src (404) which is probably the result of Bitbucket sunsetting Mercurial support.
Could you please publish the repository elsewhere? (Or if you already did, what is the new location?)
I noticed that there is a snapshot of the latest version in the Download section, which is now 20.2.0, but older versions are not accessible. It was very convenient to browse repository history to see all changes in the SDK, what was changed/added and when. We used this information when we had to update modules written for older versions of FlexSim.