How to upgrade:
- Check if you have
/usr/share/firmware-librem5-nonfree/firmware/brcm- If you do skip to install spark lan
- If you only have
/usr/share/firmware-librem5-nonfree/firmware/that is not enough. - Flashing the device with https://source.puri.sm/Librem5/librem5-flash-image is not enough
- You must follow steps in https://source.puri.sm/Librem5/librem5-fw-jail
- I was confused why this referenced librem5-devkit-tools and thought it may be out of date. It isn’t, it’s just not what I expected.
- Install spark lan
- You remove the back cover
- Remove the cover for the wifi and modem modules (3 screws)
- Unplug the antennas for both modules
- Remove the mid cover (all outer screws and 1 screw in each module compartment)
- Reroute the longest cable from it’s snake and hide it down the right side wall
- Replace the mid cover making sure the antennas aren’t squashed
- Note any golden pins :D. (credit to Chris - Camera kill switch not working?)
- Insert the modem and it’s antennas
- Insert the new wifi and it’s antennas
- Replace mid cover
- Replace screws in the module compartment
- Replace module cover
- Feel free to test at this point if you like
- Replace side screws
- Replace back cover
My Experience:
I got the impression that a fully updated phone would just work swapping out the card. This isn’t really true. To be extra cautious I figured I’d even go as far as re flashing the whole phone. This didn’t work either. You must use the instructions in librem5-fw-jail. If it wasn’t for community members in this thread and @dos, I don’t think I would have got this working at all. It really really needs a follow up post and link to instructions when shipping out the module. Right before I went to flash the firmware on it I had some rattling going on and found Chris’ post on the golden pin (TY!). Also no idea if I did this but the volume rocker seems to fall out pretty easily now. fixed 
See my reply if you have this issue.
So far local music bluetooth playback on a pair of jabra elite 75t is awesome. Where it used to periodically stutter, to a point I wouldn’t use it, it is much smoother now. It will stutter if you leave setting open with it scanning, but once I closed that 0 stutters. I think I read a comment that while on the internet it would fail. In my short experience so far, firefox streaming youtube and bluetooth audio has no stutters. Initially I wasn’t seeing the same kind of speed improvements others had. I went from ~20 down to ~10 Mbps. I thought that was weird so I got cozy with the router and got 126/134 Mbps. Then back in the office I got 20 again which is nice. While doing that I left the local bluetooth music streaming going, still no hic ups. 
All in all I think this solves one of the most annoying things about the L5, and I’m very pleased :). Now I just need to bring myself to contact support about gps.