A quick summary would be that GMAC is reducing Quant and Verbal and making the IR section more important.
Please note these changes are not all confirmed by GMAC itself but fair to say the impression is:
The new GMAT will be launched in Q4 2023
Sentence Correction will be taken out
AWA will be taken out
The IR will include DS questions
Geometry won't be included
The 3 sections - new IR, reduced Quant, and reduced Verbal - will play a part in calculating your total score out of 805
Each of the sections will be 45 minutes long
Answers for up to 3 questions per section can be changed
Current GMAT scores should still be valid for 5 years from the time of taking. In case you've already been studying and would rather stick to the current version, it will still be available for you to take "until early next year" (MBA website).
GMAT Knight - Online GMAT Tutoring
Verbal 99% V48 - Quant Q50 [Section Bests]