Is it OK to delete older versions of Windows 10 SDK?

I just installed the latest SDK(10.0.10586.0) and was wondering if I can delete the libraries from the older Windows 10 SDKs(10.0.10240.0 and 10.0.10150.0)?

Or is there a safe way or a program to do this?

You can uninstall the older versions via Add/Remove Programs. It maintains a different entry for each version.

If storage space is a pressing issue for you, you can proceed to delete the older SDKs. Deletion can be done via program files in pre Windows 10 Creators Update builds or from Settings in newer Windows 10 builds. However an ideal software should provide a good backward compatibility at least within a major version of Windows which at this point is Windows 10.

Imagine someone with an early build of Windows 10 being unable to download your app from the store. You lose users/customers just because they have to update their OS all the way which many avoid altogether.

Keeping the older SDKs will allow you choose a minimum Windows 10 build that your app should support and hence allow installation from devices on those builds.

If you need to target specific builds of Windows, then you might want to keep older SDKs around. As new SDKs come out there may be functionality added that isn't supported by older builds of Windows, then your code will not run on that build. Generally you want to use the newest SDK available that works for your targeted audience.

I have many versions and I am not sure which to delete. I found How to move Windows Kits Folder to other disks? So if space is the problem then you can move the Windows Kits folder to another drive. That post says to move the Windows Kits folder to another drive and then with administrator privilges use the following:

mklink /J "C:\Program Files (x86)\Windows Kits" "D:\Windows Kits"

That creates a junction; joins the folder in the C: with the folder in the other drive.