Running v0.43 - Outlook 2019 crashing as of this morning

I am running v0.43 (for compatibility with a handful of clients running Outlook 2010, working to migrate them to Office 2019). As of this morning, all my clients running Office 2019 are unable to launch Outlook if my an account has been configured against my mailserver. It launches fine to profiles that don’t include my mailserver.
No error is displayed. Issues occurs in safe mode as well as after a repair / full uninstall and reinstall of Outlook 2019.
Eventviewer contains the following crash event:

*Faulting application name: OUTLOOK.EXE, version: 16.0.13001.20266, time stamp: 0x5ef2a169*

Faulting module name: mso98win32client.dll, version:, time stamp: 0x5ef2771f
Exception code: 0xc0000005
Fault offset: 0x00000000000beef2
Faulting process id: 0x2540
Faulting application start time: 0x01d65acc02c9d780
Faulting application path: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE
Faulting module path: C:\Program Files\Common Files\Microsoft Shared\Office16\mso98win32client.dll
Report Id: f949a615-2a0b-4e77-9115-67bb69122c2c
*Faulting package full name: *
Faulting package-relative application ID:

The following updates were installed recently on my mailinabox server:

Start-Date: 2020-07-14 06:14:41
Commandline: /usr/bin/unattended-upgrade
Upgrade: linux-libc-dev:amd64 (4.15.0-109.110, 4.15.0-111.112)
End-Date: 2020-07-14 06:14:42

Start-Date: 2020-07-14 06:14:45
Commandline: /usr/bin/unattended-upgrade
Install: linux-headers-4.15.0-111-generic:amd64 (4.15.0-111.112, automatic), linux-modules-4.15.0-111-generic:amd64 (4.15.0-111.112, automatic), linux-image-4.15.0-111-generic:amd64 (4.15.0-111.112, automatic), linux-modules-extra-4.15.0-111-generic:amd64 (4.15.0-111.112, automatic), linux-headers-4.15.0-111:amd64 (4.15.0-111.112, automatic)
Upgrade: linux-headers-generic:amd64 (,, linux-image-generic:amd64 (,, linux-generic:amd64 (,
End-Date: 2020-07-14 06:15:35

Start-Date: 2020-07-15 06:34:55
Commandline: /usr/bin/unattended-upgrade
Remove: linux-headers-4.15.0-101-generic:amd64 (4.15.0-101.102)
End-Date: 2020-07-15 06:34:58

Start-Date: 2020-07-15 06:35:01
Commandline: /usr/bin/unattended-upgrade
Remove: linux-image-4.15.0-101-generic:amd64 (4.15.0-101.102), linux-modules-4.15.0-101-generic:amd64 (4.15.0-101.102), linux-modules-extra-4.15.0-101-generic:amd64 (4.15.0-101.102)
End-Date: 2020-07-15 06:35:07

Start-Date: 2020-07-15 06:35:10
Commandline: /usr/bin/unattended-upgrade
Remove: linux-headers-4.15.0-101:amd64 (4.15.0-101.102)
End-Date: 2020-07-15 06:35:12

Start-Date: 2020-07-15 06:35:15
Commandline: /usr/bin/unattended-upgrade
Remove: linux-modules-4.15.0-108-generic:amd64 (4.15.0-108.109), linux-image-4.15.0-108-generic:amd64 (4.15.0-108.109), linux-modules-extra-4.15.0-108-generic:amd64 (4.15.0-108.109)
End-Date: 2020-07-15 06:35:20

Start-Date: 2020-07-15 06:35:23
Commandline: /usr/bin/unattended-upgrade
Remove: linux-headers-4.15.0-108-generic:amd64 (4.15.0-108.109)
End-Date: 2020-07-15 06:35:24

Start-Date: 2020-07-15 06:35:27
Commandline: /usr/bin/unattended-upgrade
Remove: linux-headers-4.15.0-108:amd64 (4.15.0-108.109)
End-Date: 2020-07-15 06:35:29

Any idea what could be causing this, or how I can go about troubleshooting and resolving?

It sounds more like an Outlook 2019 issue other than a MiaB issue - otherwise errors would be on the connectivity scope other than plain crashing.

Looking at the errors spewed by the client it seems to indicate a memory violation (the equivalent to a segmentation fault) at one of the modules. Did Microsoft release an update recently to Outlook?

I’m thinking you’re on to something here. On further examination, there are a variety of non-miab accounts I can add to outlook that trigger the same behavior - gmail, Office 365, and Office 365 GCC-High accounts all lead to the same crash. Somehow adding and hotmail accounts doesn’t seem to. Adding MIAB server via IMAP or ZPush crashes as well, but obviously that means nothing here.
Thanks for the input,

It’s possible that there were changes to Outlook’s IMAP/IMAP+TLS module so that it is no longer handled correctly - it’s also possible that Hotmail uses a different/proprietary protocol (because two Microsoft products) and as such does not crash, but I’m speculating here.

Found the fix by tweaking my googling and narrowing down my search to very recent posts -

cd "\Program Files\Common Files\microsoft shared\ClickToRun"

.\OfficeC2RClient.exe /update user updatetoversion=16.0.12827.20470