Not too big a deal for older drones. ID rules specifically say that drones made prior to the rules are not subject to them.
. UAS without Remote Identification Equipment
Under the proposed rule, the vast majority of UAS would be required to have remoteidentification capability, however as discussed in section X. A. 3,a limited number of UAS would continue to not have remote identification.The FAA envisions that upon full implementation of this rule, no unmanned aircraft weighing more than 0.55 poundswill be commercially available that is not either a standard remote identification UAS or a limited remote identification UAS. However, there will be certain UAS including amateur built aircraft and previously manufactured UAS that might not have remote identification capability.Apersonoperatinga UAS without remote identification equipmentwould always be requiredto operate within visual line of sight6and withinan FAA-recognized identification area.
Note the I suspect drones as old as a Mavic Pro may already have a form of this implemented after the early firmware 1.04 (Do I have that correct?). That is why you got somewhat reduced range as they added a remote identification channel in favor of better signal. I noticed this when flying 1.06 and downgraded back to 1.04. About this time, DJI also released a whitepaper for remote drone identification for law enforcement.