Annex F has always been Informative and not Normative. Except for safety valves (SSV, USV, BSDV), which are required to be validated to PR2F per section 14.17.2.3.3 and Table 62, Annex F is only required if specified by the manufacturer or purchaser.
PR1 was removed from Annex F in the 21st Edition because the Annex F PR1 requirements were unclear, didn't add much value, and were likely to result in confusion.
The API 6A PR1 validation requirements are per the manufacturer's procedure.
The relevant validation requirements are in API 6A 21st Edition Section 5.5:
Additionally, there are performance requirements (for PR1 and PR2) in some of the equipment-specific sections. Most of these requirements are very vague - the equipment is required to be capable of performing a certain number of cycles, but what a "cycle" consists of is not defined.
PR1 was removed from Annex F in the 21st Edition because the Annex F PR1 requirements were unclear, didn't add much value, and were likely to result in confusion.
The API 6A PR1 validation requirements are per the manufacturer's procedure.
The relevant validation requirements are in API 6A 21st Edition Section 5.5:
5.5 Design Validation
Manufacturers shall document their design validation procedures and the results of design validation.
Design validation shall be performed in accordance with Annex F when specified by the manufacturer or purchaser.
Manufacturers shall document their design validation procedures and the results of design validation.
Design validation shall be performed in accordance with Annex F when specified by the manufacturer or purchaser.