The revised rules (2023 version) for FAI F4B are available at https://www.fai.org/page/ciam-code.  The markup clearly shows the changes, including:
1.    Secondary Control Functions (including but not limited to control of engine/s, landing gear, landing flaps) can be controlled using 2.4GHz radio control equipment with the transmitter under the sole control of the pilot in the center of the circle during the flight.
2.    F4B models shall be static judged to the same rules set at F4H static judging (where all static judging is carried out at a distance of 5 meters).

The AMA rules for other scale events (2022-2023 version) are available at https://www.modelaircraft.org/sites/default/files/Control%20Line%20Scale%202022-2023_0.pdf.

PM me if you have any questions.

Pete

I am glad to see 2.4 Ghz in the F4B rules. We have been lucky that the AMA rules made 2.4 Ghz legal in 2013, it's been a game changer.