No, cookie1424, ETS has not changed any of its speaking criteria or scoring standards. Unfortunately, with just a 4-point speaking rubric, I think it's possible to improve and still be at the same score level.
Since you are consistently scoring at around 22 - 24, you are basically getting 3/4 on almost every question. You may have improved somewhat on your most recent exams, but still are in that same 3/4 range (but higher). For example, you may be doing better in one or two of the 3 scoring criteria (delivery, language usage, and/or topic development) but still not quite hitting 4/4 level in one or two others. To earn a 4/4 on any speaking task, you must be at level 4 (as described in the scoring guide/rubric) in ALL THREE areas. Even if your delivery and language usage were outstanding, for example, you would still earn just a 3/4 if the rater determined that your "topic development" was not specific enough and you did not support your general ideas well.
My advice to you would be to take a class or find a trained teacher who can listen to you live or your recordings and point out why you are consistently scoring 3's on nearly all of your speaking tasks. Hopefully, that will help push you up into the 4 range.
Best of luck to you.