Either "on a side note" or "on a different note" could be used. The difference is that "on a side note" implies a conversational shift to a related topic while "on a different note" implies a conversational shift to an unrelated topic.

On a slightly different note, here is a useful page on docker data containers.

On a parallel note, I'm glad to announce the API changes for the genes/transcripts upload are available for you to try on the development server.