V1.17 is indeed the one made for NeoLemmix V1.43.
Until V1.47 of NeoLemmix, the associated tools (except the editor) had their own independent version numbering, unrelated to NeoLemmix's. This is why they don't match up in this case. From 1.47 onwards, the version numbering is the same across all tools. (IE: player 1.47, editor 1.47 and flexi 1.47 all match up to each other)
With that being said, once again: The intent of old versions being available is in case they're needed for playing or upgrading older content. New content really should not be created for old versions; all new content should either target the current stable version (10.13.18) or upcoming versions (11.xx.xx); preferably the stable one, unless some feature from the upcoming version is critical to the pack.