I am a novice, who can tell me what the difference of 2.0.0a and 1.10.1d? I did not find out the answer on the website.

Don't bother with the differences. You should be using 2.0.0a. Actually it might be better to start with 2.1.0 WIP 6 already as it is feature complete and will soon replace 2.0.0a.

In 2.0.0 I fixed issues that I discovered with 1.10.1, for example parameter references are not safe in 1.10.1. Also 1.10.1 allow the script to store pointers without any automatic management, which also is not safe. 1.10.1 is only available for those projects that are still using them, and should a critical bug be found I promise I will fix it, but I will not be doing any further development on 1.10.1, as I've moved on to 2.0.0 already.