The rules of snooker have been updated by the WPBSA and came into force on August 15th 2019.

You can view the changes here – https://www.wpbsa.com/governance/rules-of-snooker/

The main change is as follows –

Section 3 Rule 14 Foul and a Miss In paragraph (a), the previous option of calling a FOUL AND A MISS when, before or after a stroke, the points available on the table are equal to the points difference excluding the value of the re-spotted Black is deleted. The referee may now call FOUL AND A MISS in this situation.