Hi, @Dave Franklyn
Thank you for posting in Microsoft Q&A forum and thanks very much for your feedback.
We're glad you found the answer from the official documentation, here is a more detailed article to explain it, for your reference:
https://craigtwall.com/how-sccm-became-memcm-or-just-configmgr/ And you mentioned there are two different downloads: SCCM Ver 1902 and MECM Ver 2203.
Because SCCM is a part of the "System Center" suite when the SCCM current branch version is 1902, but it removed from that suite after version 1902, and version 1902 is out of support now.
The latest baseline version is MECM 2203, it's recommended to download and install the MECM Ver 2203.
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