What's fixed (and what isn't) in Windows 10 Mobile Insider Preview build 10136

It's been just over a month since Microsoft rolled out its last Windows 10 Mobile Insider Preview, build 10080, to the Fast ring. Microsoft didn't exactly win the love of the community with that release - as many of our readers pointed out, 10080 had more than its fair of bugs, quirks and stuff that just didn't work.

Of course, this is pre-release software - and the whole point of the Windows Insider program is to help Microsoft find those bugs and squash them ahead of the operating system's launch later this year.

Today, the company rolled out Windows 10 Mobile Insider Preview build 10136 to the Fast ring, bringing various new features and improvements, along with a range of fixes for some annoying bugs and issues in the last build, which Microsoft has documented in its release notes:

• We have fixed the MMS bug in Build 10080, and you should receive MMS messages normally.
• We have fixed the issue where touch will stop responding on the Lock screen preventing you from swiping up to unlock your phone.
• We have fixed some visual glitches in Action Center when expanding/collapsing.
• We have fixed the issue where the text in the People app was too small.
• When you toggle the Wi-Fi quick action in Action Center, it now disables/enables Wi-Fi instead of taking you to the Wi-Fi Settings page. This was one of the top 5 pieces of feedback we heard from Windows Insiders.
• Your Start screen background should be scaled correctly now.
• You can add a detailed status to display on your Lock screen from apps like Outlook Calendar without having the Settings app crash.
• We also fixed the issue where a mouse cursor would appear when pressing the back button on your phone.

However, some issues remain in build 10136, including a very significant bug that prevents devices running build 10080 upgrading to the newest release. That means that anyone on 10080 wanting to install the new build will first need to use the Windows Phone Recovery Tool to roll back to Windows Phone 8.1, and then access the Fast ring update to 10136 from there via the Windows Insider app.

But aside from that, there are various other known issues with build 10136, as Microsoft explained:

• After upgrading, you will still see duplicate tiles for apps like Search and Phone under All Apps.
• If you have too many PIN unlock attempts, you’ll see the “enter A1B2C3” reset experience. However, there is an issue in this build where after you enter the code you won’t see the PIN pad. The workaround is to press Emergency Call after entering the code, then press Back and you’ll be able to enter your PIN.
  • We recommend disabling the double-tap-to-wake feature on some Lumia devices by going to the Settings app then Extras > Touch > Wake to prevent any accidental PIN unlock attempts.
• There is an issue that may cause Skype not to work after upgrade. The best workaround is to uninstall Skype on Windows Phone 8.1 *before* you upgrade to this build and then reinstall it after upgrading. If you miss that step though, you can usually resolve by uninstalling it and reinstalling from the Store once you’re on 10136.
• If you’re having issues installing new Language Packs in this build, see this forum post.

Microsoft also posted a paragraph which you should really take notice of, given that it introduces some key information by highlighting that it's "SUPER IMPORTANT TO READ THIS:"

At the end of the upgrade the Lock screen will appear frozen without the date and time for up to 10 minutes. Please be patient and let it sit – eventually the date and time will appear and it will allow you to unlock your phone. There is a post-upgrade migration status screen missing, which normally would show you that it was making progress. If you get impatient and restart or mess with locking/unlocking your phone, you’ll wind up in a funky state – so just relax and let it do its thing.

This isn't an exhaustive list of bugs and issues in the new preview, so there's a good chance you may encounter a few that aren't documented above. If you spot any particularly annoying or persistent issues, let us know in the comments below!