Should I update my Mavic Mini to the lastest Firmware? or is this just for the Mine 2?   

Are you referring to DJI Fly APP version 1.2.2 or to Mavic Mini 2 Firmware? I updated my DJI Fly App to 1.2.2 and did some tests with good results.
For Mavic Mini, I didn't notice any new firmware (for the drone).

Regards.

Hello there MeFlyMore. Thank you for reaching out and for these information you have posted. In addition to this post the DJI Fly v1.2.2 has the following updates:
- Adds a new Attitude Indicator: Learn more about your aircraft’s orientation and flight info.
- Adds Flight Tips: View interesting aerial photography tips during scenarios such as firmware updates, taking hyperlapse shots, and when the aircraft is returning to home.
- Adds the following supported functions for the Customizable Button on remote controller: Gimbal Follow/FPV, Camera Settings, and Exposure Lock/Unlock.
- Fixes certain issues and optimizes overall app quality.
Thank you.

Adds the following supported functions for the Customizable Button on remote controller: Gimbal Follow/FPV, Camera Settings, and Exposure Lock/Unlock.

What customizable button on the remote control?  Or is this yet another thing that does not apply to the Mini?

K6CCC Posted at 1-4 21:29
Adds the following supported functions for the Customizable Button on remote controller: Gimbal Follow/FPV, Camera Settings, and Exposure Lock/Unlock.

What customizable button on the remote control?  Or is this yet another thing that does not apply to the Mini?

Yes, it is button on new style remote control unit of MA2 (Mini2 very likely)...

virtual Posted at 1-5 01:54
Yes, it is button on new style remote control unit of MA2 (Mini2 very likely)...

Thanks.  Glad to see I'm not loosing my mind...

K6CCC Posted at 1-5 07:46
Thanks.  Glad to see I'm not loosing my mind...

Yes, there was "customizable button" on the remote control with only 2 or 3 options, now there are 3 more for MA2 (and Mini2?)... RTH button on Mini1 remote instead of customizable button if I remember.

DJI Stephen Posted at 1-4 20:43
Hello there MeFlyMore. Thank you for reaching out and for these information you have posted. In addition to this post the DJI Fly v1.2.2 has the following updates:
- Adds a new Attitude Indicator: Learn more about your aircraft’s orientation and flight info.
- Adds Flight Tips: View interesting aerial photography tips during scenarios such as firmware updates, taking hyperlapse shots, and when the aircraft is returning to home.

So we are in the mavic mini, not mini 2 forum section... Still your automatic response relates to the Mini2... Seriously not sure what's wrong with DJI customer support...
An absolute joke...

K6CCC Posted at 1-5 07:46
Thanks.  Glad to see I'm not loosing my mind...

We used to have these custom buttons on Spark RC... I don't know why DJI removed from Mavic Mini RC!?!?!

InspektorGadjet Posted at 1-5 12:01
So we are in the mavic mini, not mini 2 forum section... Still your automatic response relates to the Mini2... Seriously not sure what's wrong with DJI customer support...
An absolute joke...

They have forgotten the Mini 1 even exists so most likely immediately assume everyone is talking about the two.

unpluggeduk Posted at 1-5 15:33
They have forgotten the Mini 1 even exists so most likely immediately assume everyone is talking about the two.

The new compass is available on the MM and on the M2 and the added button option is on the M2.
The new compass is great.