AMS2420F results from a Five-Year Review and update of this specification with additions to ordering information regarding thickness of plate, and test specimens for solderability test, clarified that under plate per AMS2418 be Type 1 (3.2.2), added that multiple layers of plating shall be a continuous process so that drying does not occur between layers (3.2.2.1), added that AMS’s for sub layers of plating shall have their test requirements be fulfilled by AMS2420 testing (3.2.2.2), updated fixture contact locations (OI, 3.2.3, 4.4.3), added allowance for direct dimensional inspection (3.3.1), added that solderability test is destructive (3.3.4), added requirement for composition testing of Class 2 plating (3.3.5, 4.2.2), clarified thickness testing (4.2.1, 4.2.2), added standard wording for suspension of periodic testing (4.2.2.1), updated lot definition (4.3), added that test samples shall be randomly selected from the lot (4.3.1), changed Table 1 sampling for up to seven parts in lot, added thickness to periodic sampling and testing (4.3.2), added test specimen requirements for composition and solderability (4.3.3.2, 4.3.3.3), added method for reflowing plating to control factors (4.4.3), and clarified resampling and retesting (4.6).