What is the difference between board XBP9X-DMRS-001 rev E and rev F?

We have two DIGI XBee PRO SX boards and one is XBP9X-DMRS-001 rev E, the other is XBP9X-DMRS-001 rev F. What is the difference between the two?

The revision history of user guides are described in the user guides:
https://www.digi.com/resources/documentation/digidocs/pdfs/90001477.pdf

page 2:
E May 2017 Added GPIO specifications. Updated BroadcastTxTime formula.
F May 2018 Added note on range estimation. Changed IC to ISED

I saw that, but I tought it was the revision history of the user guide itself.
Thanks