This information may be handy for other system admins that are having issues with users trying to get their email on their iPhone, iPads and Android devices after Exchange 2010 Roll Up 25 is applied.
We started getting calls from users that their Phones and mobile devices couldn't connect to their emails and an initial investigation revealed all services were functioning as expected. No errors in the event log and the server seemed to be functioning normally. OWA worked as expected as did any Outlook clients connecting to the service. Email could be sent and received normally through those methods.
We had carried out numerous updates over the weekend to the server so decided to see what updates were applied to see if uninstalling may fix the issue. Looking through the installed list I was expecting to see the dates of the installed service as well as Roll Up 25 for Exchange 2010.
Nothing with Saturday's date of 9/1/2019 was listed. Weird! So I checked the version of exchange that was installed and instead of it being build 14.03.0435.000 it was showing as build 14.03.0419.000 which was released September 2018.
I decided to download Roll Up 25 manually and apply from here, to see if that rectified the problem. When I tried to install the downloaded file Exchange2010-KB4468742-x64-en.msp it refused to install due to the server not having Visual C++ Redistributable Packages for Visual Studio 2013. Now we're getting somewhere!
I downloaded the Visual C++ Redistributable Packages for Visual Studio 2013 from here and installed it. Bingo! Now when I check the version of Exchange it shows as version 14.03.0435.000 which is correct. Also, checked the installed updates and all the updates that were installed on Saturday are now showing up in the Installed Updates control panel.
I test that the clients can now get their email via the mobile devices and everything is now working again. Winner, winner chicken dinner! 🙂
It seems that the issue was that Visual C++ Redistributable Packages for Visual Studio 2013 is a prerequisite for Roll Up 25 and other Windows services but doesn't get flagged as such in WSUS.
As a side note, you should also ensure that your server SSL certificate is current because this can cause issues with the authentication process.
If you're using an iPhone you may need to do the following on the phone:
Settings->General->Reset->Reset Network Settings
Hope this has saved you some time...