I am not familiar with the platform, but perhaps its like Steam where they've got only the stable versions?Kinda ironic how I paid for this game a while ago, but Gamejolt version is outdated AF. Thanks for the updates, at least I can see what might be included in next update I paid for, whenever that happens...
If so, then its normal and to be expected.
For the newest/alpha builds, the legit way to get them is by being a Patreon, afaik.