uninstalling .net 4.0 and having .NET Framework 4.6.1 instead


I am maintaining a web application which is compiled in 4.0 and it is under IIS 7.5. In the machine, i can see 4.6.1 is in place.

In the application pool, I saw .NET 4.0 is selected but it is not clear for me whether it is using 4.6.1 or 4.0 after seeing this http://forums.asp.net/t/2068374.aspx?Is+IIS+7+5+capable+of+hosting+applications+targeting+NET+Framework+4+6+

My issue is that admins will be uninstalling 4.0, 4.5 and 4.5.1 since the EOL period for them is approaching and plans to keep 4.6.1

My first question is that is my application really running on 4.6.1 (since it is not clear for me on IIS) or on 4.0?

My second question is that if .NET 4.0 is uninstalled from the server environment, does this mean the binaries compiled in 4.0 will break?

LVL 12
Who is Participating?
David Johnson, CD, MVPConnect With a Mentor OwnerCommented:
I would reverse the order uninstall 4.0 and install 4.6.1 or you risk breaking .net
David Johnson, CD, MVPOwnerCommented:
don't uninstall just ensure that an updated version is installed.
check the value of HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full \Release
378389       .NET Framework 4.5
378675       .NET Framework 4.5.1 installed with Windows 8.1
378758       .NET Framework 4.5.1 installed on Windows 8, Windows 7 SP1, or Windows Vista SP2
379893       .NET Framework 4.5.2
393295 (Windows 10) or 393297 (All other OS versions)       .NET Framework 4.6
394254 (Windows 10) or 394271 (All other OS versions)       .NET Framework 4.6.1

.net 4.x.x are backward compatible to earlier versions of .net 4.x.x
jazzIIIloveAuthor Commented:

.NET Framework 4.6.1 will be installed before uninstalling 4.0. Is it still safe? All the binaries are compiled with 4.0. Would it work just fine?

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.