You may have seen posts about todays CCSA meeting. Basically they’ve said from October 1st (until March 31st 2023) visa exempt entries will get a stamp for 45 days (up from 30). Visa on arrival, for the counties that pay 2,000 baht on arrival will be 30 days (up from 15).
Although there is no details about extensions it’s widely believed that they will remain unchanged. Visa exempt and tourist entries will still be able to apply for a 30 day extension (edit: for those countries eligible). Visa on arrival is not eligible for extensions.
This has yet to be published in the Royal Gazette so is not yet law but widely expected to be so in the coming days.
TLDR : Answer Summary
Starting October 1st, 2022, visa exempt entries to Thailand will now receive a 45-day stamp instead of 30 days, while visas on arrival will increase from 15 to 30 days for participating countries. Extensions remain available for visa exempt and tourist entries, allowing an additional 30-day extension for eligible countries, while visa on arrival entries are not eligible for extensions. Although these changes have been widely discussed, they are pending official publication in the Royal Gazette.