Phantom Premier vs Phantom I

[struts]

I've got a pair of gold N07 's  from 'new stock' ~5/2020. They run MUCH cooler with any use, compared to the silver H (something) (no airplay but has BT) and Silver L (something) (airplay and BT) series at idle.

Interesting @scotthar.  What are the last 4 digits of the serial number on those Golds?  I just stumbled over an old thread which reminded me that @Bbnsound reported that the new internals appeared in (Glossy White) Golds whose serial numbers end 4U10* (this was corroborated by a number of users).  Sorry folks, I had completely repressed this.  I checked my K28 (mid-2017) Golds whose serial numbers end 4U06 and both are MX207 models so this definitely does not signify new hardware.  So the question is when did the 4U10 units come into production?

@djredeye, @LiRnCHO please could you also check the last four digits of the serial numbers on your units and post here.  Also, if you can post the model numbers we can maybe start laying the puzzle to try to see (a) when the new ("V4?") hardware actually went into production and (b) if any correlations exist between serial numbers and model numbers.

* Whereas the new Phantom I 108dB models (at least initially) had serial numbers ending 4U13 (dark chrome) and 4U15 (matte white)