What is the impact to install Microsoft .NET Framework 3.5?


I need to install Microsoft .NET Framework 3.5 on all Windows servers and I noted that there are some Windows 2003 are missing that version, they have Microsoft .NET Framework 2.0.

The reason why I need to install it is because a monitoring application required that to work.

My question is: Is there any impact to install it? I mean can this affect the applications already installed in the servers?

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

timgreen7077Exchange EngineerCommented:
Generally you should be fine to install it. .Net version can generally work together so the application will use the version it needs as long as it's installed. You can have multiple versions of .Net installed and it generally doesn't cause issues.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
bbaoIT ConsultantCommented:
i don't think you will have problems with existing applications. basically all existing applications should be using .NET 2.0 or even earlier, so the the framework 3.5 has nothing to do them. actually 3.5 will be installed in a separated folder at all. hence technically no runtime codes will be mixed.
As others have said, there should be no conflict. However, I would be cautious about using a program that relies on such an old, old version of the .NET framework, especially if it needs to do any communication over the network. Version 3.5 did not have all the security protocols that we have today so there's a high risk of the application trying to use old security protocols that could be dangerous to allow.

Also, I would expect any application that is still under active support to occasionally be updated to user the newer framework versions. So if an application is still on 3.5, it may indicate an application that doesn't receive a lot, if any, attention from the developer.
CompTIA Security+

Learn the essential functions of CompTIA Security+, which establishes the core knowledge required of any cybersecurity role and leads professionals into intermediate-level cybersecurity jobs.

You have to review the functionality of your existing application and check whether the installation of .net 3.5 includes the prior versions, but on install will register itself and might cause sone application to fail because they rely on tools/functions that the new version altered, does not support or were modified to enforce Sevurity.

Only way to know for sure, is test on an equivalent system.

Just to mention, 2003 is a ....
Gustav BrockCIOCommented:
We have two 2003 servers running with both .NET 2.0 SP2, 3.0 SP2, 3.5 SP1, and 4.0 installed.
Zero issues, neither should there be.
Raja Jegan RSQL Server DBA & Architect, EE Solution GuideCommented:
As already mentioned by other experts above, ideally you should haven't any issues.
But I would recommend to create a test machine with the same OS and application versions and test installing .Net Framework 3.5 on the test machine to verify once before touching the actual servers..

>> I noted that there are some Windows 2003

Why still using Windows 2003, Windows 2003 crossed your End of Life Support long time back..
Kindly check for any possibility to upgrade your Server and Application to latest version with the help of your Application vendor..
SAM2009Author Commented:
I just hope it will not make the local application switch from NET 2.0 to 3.5 automatically.
An application is "targeted" against a particular .NET version when it is built. An application that is built / targeted against .NET 2.0 can only use .NET 2.0. Similarly, an application that is built against .NET 3.5 will only use .NET 3.5. It doesn't matter if the other versions are installed.

The only slight exception to this is .NET 4.x. All the .NET 4.x versions are backwards compatible all the way back to 4.0, so if an application is built against .NET 4.0 and you have .NET 4.7 installed, it will use .NET 4.7.
You should test, but if it might, c:\windows\net.framework if I recall the path,
There is a way to reassert .net 2.0

Often, issues only arise if/when the software vendor distributes a specific .net related installer.
SAM2009Author Commented:
Is installing NET 3.5 can affect SQL DB?
No. Again, installing .NET 3.5 will not break any programs or applications or services that are already running on a different version of .NET.

If a program is already running without .NET 3.5, then it will keep running after you install .NET 3.5.
No, commonly .net upgrades can only impact custom application where the vendor used/relied on features/function that ms later determined were insecure or a security risk and implemented restrictions that could break the application.

We seem to be going back and forth with incremental injection of additional info.

The only way for you to minimize possible impact is to test the installation of .net on a test system.

If your environment contains redundancy, make sure you have a backup, install on one ...

Then progress to the next.
SAM2009Author Commented:
Thanks for sharing your comments!
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
.NET Programming

From novice to tech pro — start learning today.