How to downgrade a Windows Phone 8 app? - windows-phone-7

I originally made an app for WP7 then a while later decided to do a complete overhaul of UI and code which is when WP8 came out so I took down the old app and made a new one specifically targeting the newest platform, however I now want to 'port' it back down to target the old audience as well.
I've had a few attempts but it seems to be a tedious task, is there any easy way to do this?
Thanks.

As per the above answer there is no automated way to revert the projects; however I usually separate out as much logic as I can into a Windows Phone class library which can be shared by both Windows Phone 7 and 8 projects. So my advice is to copy across what you can (VMs, Services, etc.) to a separate class project, setup a new Windows Phone 7 project, and bring across your WP8 views and remove any incompatible bits such as the new maps control and reference the shared library between both platforms.

No, unfortunately you cannot downgrade a windows phone 8 project to windows phone 7. You can only upgrade a windows phone 7 project to windows phone 8.

Related

Windows Phone 7 project not updating properly

Using VS2015 I upgraded a WP 7.1/7.7 project.
I was developing and testing fine using the 8.1 emulator for a couple of months until I realized that I was missing then newer 8.1 controls in the toolbox.
I started a new separate 8.1 project and I can see a large range of new controls like Listbox and ComboBox that don't exist in the 7.1 upgraded app.
Looking at the project properties the Target Windows Phone OS Version is set to Windows Phone 8.1.
I've searched all over and can't find any other settings to tweak.
The project has the older Windows Phone Toolkit 4.2013.8.16.
I wonder if that blocks the new tools?
How can I get the 8.1 one controls to turn on?
There's two frameworks on Windows Phone 8.1: Silverlight and WinRT. When you upgraded to 8.1, since your project was using Silverlight (WinRT wasn't available on Windows Phone 7), it was set to target Silverlight 8.1. That's why you can't use the WinRT controls. The thing is, WinRT and Silverlight have completely different controls, so you can't automatically convert a project from one to another. You've got to consider whether you really need/want to use WinRT. If so, you'll have to rewrite large portions of your UI code to accommodate with the new controls.
If you want to make the conversion, you should first have a look at the Microsoft documentation to understand the key differences between the two frameworks: https://msdn.microsoft.com/en-us/library/windows/apps/hh452743.aspx
Note that Windows 10 universal apps (the ones that can run on phone and desktop) use WinRT. Silverlight is deprecated, and sooner or later you'll have to upgrade.

Will Windows Phone 8 app run on Windows Phone 7?

I have some apps developed with Windows Phone SDK 7.1 which undoubtedly run on Windows Phone 8 without any change.
My question is the other way. If I upgrade my app WP7 apps to WP8, meaning I make necessary namespace changes and compile them with WP8 SDK, will they still run on WP7? - I guess no.
What should be my strategy to have apps that run on both of the OS and still I should be able to use advanced functionality (if it runs on WP8) that WP8 offers (like Wallet, NFC, Nokia Imaging and more stuff like that)?
Is that I need to create 2 separate versions of each app? One will run on WP7 built with WP7 SDK and will not have advanced functionality like Wallet, NFC Sharing. The other app will have all of them and built with WP8. Will they be two separate apps in Windows Phone Marketplace?
Windows Phone 7 apps will run on Windows Phone 8, but the reverse is not possible. The former is called backwards compatibility.
If you want to support WP 7 OS, you need to maintain two different applications and submit them independently to the store.

WP8 updates on WP7 apps

Since the release (and in some cases prior to) the release of Windows Phone 8, several WP7 apps on the marketplace have had updates that simply state "Updated for Windows Phone 8."
What does this mean, exactly? Because the marketplace allows multiple XAP uploads, is it a new XAP for WP8 but the app only allows a single description (thus "updated for WP8")? If so, does the marketplace push an update for WP7 even if the WP7 XAP hasn't changed?
Or, are there changes to the 7.1.1 SDK that optimize for WP7 apps on WP8? If so, could you provide a link outlining this? (I did a search, but all I could find is the 7.1.1 update targets 256MB devices.)
Bottom line, although I know WP7 apps are compatible on WP8, is there something I should be doing with my WP7 apps for WP8 while still functional on WP7?
Take a look at this, seems to be an issue that is being worked on at the moment.
http://social.msdn.microsoft.com/Forums/en-US/wpsubmit/thread/789b3017-d242-4151-9d0b-84c85c4b3c24
These tags of "Updated for Windows Phone 8" don't necessarily mean that the app has been upgraded to a Windows Phone 8 application. It could also mean that the developer has tested and fixed bugs that can break functionality for a Windows Phone 7 app in Windows Phone 8. For example, I found two bugs involving local storage in Windows phone 7 projects when running on Windows Phone 8. Therefore, I had to make some adjustments to get my project running 100% on Windows Phone 8 (but its still a WP7.1 project). For more information on bugs and "quirks" when running WP7.1 projects on Windows Phone 8 here is a link to Microsoft's information.
http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj206947(v=vs.105).aspx

Developing for the windows slate

as Microsoft are releasing a tablet later this year, with a new operating system I was wondering whether we can already create apps for this platform and have them on the market place prior to release?
If this is the case where could I get my hands on the API's needed to go about creating a touch application in XNA for the upcoming windows 8 tablet.
Right now it looks like XNA applications will not be directly supported by the marketplace (source); however, MonoGame games are able to get into the Marketplace. This is an open-source alternative to XNA.
At this point, consider XNA to be around for a few more years but not directly supported in anything other than what it currently works on Xbox, Windows Phone, and Windows but not on the Windows 8 Marketplace.

Can i use silverlight 3 or 4 dll in my windows 7 application

Would an application built using a siverlight 3 or silverlight 4 dll be allowed into the market place?
WP7 is built on Silverlight 3 with some inclusions/exclusions to suit the mobile platform.
You can pull DLLs in provided they make use only of features compatible with the platform.
For a guide to what is supported on the platform, refer to these documents.
Features Supported in Silverlight for Windows Phone
Differences Between Silverlight on Windows and Windows Phone
Class Library Support for Windows Phone
You will have to download the CTP version of the Windows Phone 7 tools (available Sept 16th) and compile your app with those for your WP7 app to be accepted into the marketplace.
It's not a matter of being "allowed", it is a matter of "will it work"? Read the details on what they expect of an app and how it works, and if they don't say you can't do what you suggest, then assuming it actually works, it should be acceptable in the marketplace.
Keep in mind that the version of Silverlight running on the release version of WP7 will not be the equivalent of SL v4. I would be surprised if a v4 DLL would work in WP7. A MS WP7 team member I heard on a podcast (Hanselminutes, I think) said that SL on WP7 is, like, SL v3.7 or so.

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