RC76xx part number changes

I have a product design based around the RC7620 and RC7611 modules. I’ve specified the RC7620_1104625 and RC7611_1104595 as the full part numbers to use as these were the available modules when we started the design process. Digikey is now showing these parts as obsolete, replaced by the RC7620_1105026 and RC7611_1105020 respectively. I’ve not been able to find any information on what the portion of the part number after the underscore actually signifies. Is there a document anywhere that explains the part numbers in more detail? Will the Digikey recommend alternatives be drop in replacements or are there better alternatives I should be considering?

Does Sierra wireless have any kind of obsolescence notification system in place I can sign up for to catch these kinds of changes further in advance in the future?

those product change notice should be shared with distributor.

e.g.

Probably you need to check with the distributor