March Progress:
Another month of testing, another month of bugs.
Fixes:
1. Wallet transaction List
It took several iterations of fixes, but we seem to finally be displaying the transaction history reliably. As part of these fixes, the code was moved to a location where we could more easily write automated tests for it. Having repeatable tests should ensure that this continues to function properly in v0.21.2, and in all future releases. You can find most of the related changes here.
2. Miner Crashes
When the mining logic was written, it was intentionally made overly simplistic at first, allowing only spends of confirmed outputs. It would not allow you to spend outputs in the same block they were created. The plan was to add support for this after launch sometime.
However, one of the testers was able to create a batch of transactions that caused mining nodes to crash when they tried to include those transactions in a block. After some investigation, we found the underlying problem, and realized that adding full support for including spends of unconfirmed outputs would resolve the issues. So that’s what was done here, along with some redundant checks to prevent similar failures from occurring.
3. Subtract Fee From Amount
We’ve had a large handful of issues related to the creation of transactions using the “subtract fee from amount” functionality. After playing whack-a-mole with these bugs for a few weeks, I finally decided it was time for a minor overhaul of the spend code. This was done here, here, and here. From what I can tell, it is working well now, but we’ll know more once testers get their hands on the rc6 release.
Release Status
I was hoping to be able to share rc6 with everyone today, but a few problems were reported last minute that needed to be fixed. I believe we’re finally ready to tag release candidate 6 and start building now though, so you should see that sometime this week. All known critical issues are believed to be fixed, so unless new ones are found during testing, rc6 could be our final release candidate. With any luck, I may be able to share the official v0.21.2 release with everyone by next month’s update 
Activation Status
I haven’t had much time to keep up with signaling, but I have been working with most of the mining pools, and I expect them all to be signaling very soon (some already are). @coblee is tracking the major pools and their statuses here. You can also keep an eye on block signaling here. Just a reminder, MWEB activates once 75% of blocks signal for activation within an 8,064 block window. We are currently in MWEB activation window 3, but we will not meet the activation threshold this window. The next one starts in about 2.5 days, at block 2,241,792.
P.S. This is my ~30th update now, and with the various other comments in here, it’s starting to get difficult just to scroll through to reference old posts. This will probably be my last update here, but I will continue on in a fresh new thread for next month’s update.