I’m definitely not happy about it, as I purposely bought a ST hub and moved everything to it when I found out that ST with Edge drivers supported the Ikea buttons, motion sensors, etc.
Others with V3 hubs that didn’t get the zigbee update are also having issues (been talking with a few on Reddit), so not really sure what’s going on.
I am in a similar situation, my Ikea Tradfri 5 button and 4 button remote both work after the update (once removed and added again).
But the 2 button on/off wouldn’t reconnect.
I do not have an Ikea Hub either to try a firmware upgrade but I have bought a Sonoff Zigbee dongle in hope to upgrade via my Raspberry Pi (should be delivered tomorrow).
The Smartthings team have been super helpful and tryed rolling back the Zigbee Stack etc. but this did not work also.
The Smartthings continue to look into this so I am keeping my fingers crossed they find the issue and resolve.
The SmartThings team is working on a solution for the Zigbee button issues being experienced. It will likely be a combination of a hub firmware fix and an edge driver fix.
Will it address the motion sensor as well?
Yes, I believe the motion sensor issue has the same root cause.
We will be rolling out Hub Firmware 0.45.9 Release shortly today, here are the release notes:
Thank you @Kianoosh_Karami
Will 0.45.9 also include a fix for the issue with IKEA Zigbee remotes and buttons malfunctioning? This has been quite painful living without these devices in the last week or so, wife is not happy as well 
My understanding…
The Edge driver has been tweaked because it was using the binding table to decide whether to use a particular group or 0x0000, but didn’t allow for the binding table not being returned with certain versions of the buttons.
The hub has been tweaked because although 0x0000 is apparently not valid, the horse has already bolted with that one and blocking it causes problems.
Something like that anyway
At this point, I recommend re-adding the devices (and apologies for having to reset your automation). The fix put in 0.45.9 will only apply to the Hubs that had not received the 0.45.8 or older, which in another way to say that once your Hub got migrated to the new Stack, that information was lost and extremely difficult to revive; many apologies about that. We went through months of testing, but we seem to have lost sight of Zigbee Groups; our Zigbee Stack Vendor also missed that.
If you are having any issues getting the devices to a functional state after the re-add, let us know and we will gladly investigate and root cause any problem.
Thanks for the update 45.9. I who had already exited the beta, will I receive it? I can’t get in anymore.
I Have now managed to get my Zigbee On/Off switches to work again after purchasing a Sonoff Zigbee 3.0 Usb dongle and updating the device firmware using Zigbee2Mqtt.
Glad to see the Smartthings team have found the cause of the issue and that all other user will be able to use their buttons again
Thanks for the detailed response, and engagement.
My Hub (V3) is running 0.45.8. I tried completely removing all Ikea Zigbee remotes and buttons, hub reboot, and re-creating the devices without any luck. The device is showing, but it doesn’t register any button clicked events.
I would be glad to provide any required information, so the team can further investigate. Which specific information would be required?
Thank you.
When do we get to test Thread for our V3/Aeotec hubs? 
ok it has updated, although unfortunately I can no longer access the beta firmware part on my profile on the site https://smartthings.centercode.com/ @alissa.dornbos could you help me?
As far as I can tell, at the start of a new beta cycle they play catch-up with new applications and then build a list of hubs to be used in that cycle. So you would expect to receive 45.9 and any succeeding 45.x releases.
I’ve had the reverse happen. I had a mismatch between my hub ID and its owner account in my profile at the start of the 44.x cycle so had to wait till 45.x before my corrected info took effect.
Thanks for the explanation, in fact received 45.9.
What I don’t understand is why beta access on my profile https://smartthings.centercode.com/ no longer works. I sent both private messages and tagged people from the Smartthings staff, but got no replies. I hope to receive the next official version of the firmware and stop with the betas
Had another try with removing and re-adding the devices, and it helped resolve the issue. All buttons and remotes are fully operational now.
Thanks again @Kianoosh_Karami
Once you’re in a beta cycle, you’re in it until the entire cycle is completed.
Received the firmware update.
The Ikea 5-button remote is working again.
The Ikea motion sensor is also working again, after removing and adding it back.
The reported battery percentage doesn’t seem accurate (37% in ST, 100% in Home Assistant Zha). Batteries were replaced last week.
I put a fresh battery in the 5-button remote and it’s reporting 100%
Hey @Diegocampy , Sorry for the late reply. I believe I have fixed your centercode account, please feel free to attempt again. We do monitor both the community and centercode just as closely.