Based on the Microsoft Lifecycle Catalog, the Mainstream Support for App-V 5.1 will end in January 2018. From this date on, only Security fixes will be made available until the End of the Extended Support in January 2023.
Details can be found in the Table below:
Since there is no replacement for App-V 5.1 on Windows 7 / 8 / 8.1 and Server 2008 R2 / 2012 / 2012 R2, customers are advised to upgrade to Windows 10 and Windows Server 2016.
Beginning with the Creators Update of Windows 10, getting Hotfixes for App-V 5.1 on those older Windows Versions will become more and more complicated with every Feature Upgrade.