So I've always known it's okay to run multiple versions of the .NET framework on a single computer (client or server alike). This question, though a bit old, talks about this.
A while back, however, I was tasked with creating a new ASP.NET application, and I was trying to decide whether to use the full .NET framework or .NET Core, and I came across this article from Microsoft. The article states that if I need side-by-side installations of the framework, I should use .NET Core. Here's the full quote:
To install applications with dependencies on different versions of
.NET, we recommend .NET Core. .NET Core offers side-by-side
installation of different versions of the .NET Core runtime on the
same machine. This side-by-side installation allows multiple services
on the same server, each of them on its own version of .NET Core.
But I thought side-by-side installations of the Framework were already possible without .NET Core? What am I missing?
The reason I ask is that I currently have an old ASP.NET application that uses the .NET Framework 2.0, and I am now working on one that uses .NET Core. I ran into some issues that got me considering switching the .NET Core app to the full .NET Framework 4.6, but that Microsoft article got me a bit confused.
The question is: will I be able to run both apps (.NET framework 2.0 and 4.6) on the same Windows 2008 R2 server without issues? If so, then what is that article referring to?
One last thing: both my apps (old and new) use Crystal Reports. There's a possibility that the new app might need a newer version of Crystal Reports than the old app. Will I be able to run different versions of Crystal Reports like this on the same server? Is this the situation in which I would require .NET Core like the Microsoft article says?
Thank you
Side-by-side installations of the framework are not only possible, they are a fact. NET 1.0, 2.0 and everything past 4.0 all have separate installations. However:
.NET 3.0 and 3.5 both use the 2.0 runtime and are therefore not truly separate.
Similarly, .NET 4.5 and all versions above all use the 4.0 runtime and are therefore not separate from each other. To further complicate things, when you install a later version, the base 4.0 runtime is actually upgraded.
Last but not least, which framework version gets picked to run your application has changed with .NET 4.0. The rules for this are rather complicated and depend on both the versions installed and the application configuration; see this article for a full discussion.
To your question, then:
Will I be able to run both apps (.NET framework 2.0 and 4.6) on the
same Windows 2008 R2 server without issues?
If .NET Framework 2.0 and 4.6 are both installed, then yes. Assuming no special configuration settings, the 2.0 application will run on the 2.0 framework, but it can also be configured to use the 4.6 framework (which will present itself as the 4.0 runtime).
If so, then what is that article referring to?
The article is referring to the fact that the full .NET Framework has gradually abandoned the idea of perfectly separate side-by-side installations by having no separations between minor version (and sometimes even major versions), while .NET Core has doubled down on the idea by allowing self-contained deployment. That is to say, not only can a .NET Core 1.0 and a .NET Core 2.0 application coexist without any risk of sharing dependencies the way a .NET Framework 2.0 and 3.5 application would, even two .NET Core 1.0 applications can exist together without sharing dependencies, something which is not possible for full .NET Framework applications. If (say) a patch is installed for .NET 2.0, it will affect all .NET 2.0, 3.0 and 3.5 applications, at least on the binary level. You cannot choose to have some applications affected by the patch and not others (although configuration switches are usually added for behavior that breaks compatibility).
One last thing: both my apps (old and new) use Crystal Reports.
There's a possibility that the new app might need a newer version of
Crystal Reports than the old app. Will I be able to run different
versions of Crystal Reports like this on the same server? Is this the
situation in which I would require .NET Core like the Microsoft
article says?
This is independent of the framework and depends on how Crystal Reports itself handles versioning. According to the manufacturer, the answer is yes, for major releases but not minor updates:
Side-by-side installation of different major release version of
Crystal Reports designer is supported since Crystal Reports 9,
because each major release version installs the software in different
directory.
You do not require .NET Core to make side-by-side installation of different assembly versions possible. What's more, even if you used a self-contained deployment of your .NET Core application, it would likely still refer to the shared installation of Crystal Reports on the machine, not to a self-contained deployment of Crystal Reports (I don't think such a thing exists; I'm not even sure Crystal Reports is currently supported on .NET Core).
Last but not least: note that some versions of .NET are no longer officially supported. The policies on what versions are supported (and where) are fairy complex, depending as they do on whether the Framework was part of the OS or not, but detailed here. .NET 4.6 has some very nasty JIT compiler bugs (fixed in 4.6.1), so you really don't want to be using it anyway, official support or no. If your server does not yet have any version of .NET past 2.0 installed, you may as well jump directly to the latest supported version for your OS (as of writing, 4.8).
Related
We distribute a .NET 3.5 assembly to more parties to be referenced and used in different applications.
We are now intending to upgrade this assembly to .NET 4.6 so it will benefit of all performance and security improvements in this .NET version and not for using new .NET features.
But we don't want to break existing applications that are using it.
Some consumer applications might still be using .NET 3.5 so they won't be able to use it, so I was thinking how about having two projects targeting two .NET versions (3.5 and 4.6), but same code files.
What would you recommend for maintaining and distributing one assembly code base for both .NET 3.5 and .NET 4.6 version lines?
Later Edit: This question is not about referencing a .NET 4.6 assembly in .NET 3.5, it's about how can a .NET 4.6 application to use my assembly and benefit of the security and performance of .NET 4.6 while running it. The 3.5 apps should continue to use my 3.5 assembly.
Look into creating your own nuget repository and publish the libraries in each specific version of .net needed. (For one package can have varying .net versions as needed).
Once in your nuget repository they have their own version and can be updated either in lockstep or differently. That way the consumers can use the target version as needed for the target .net version.
See Hosting Your Own NuGet Feeds
There seem's to be an assumption that an identical code base compiled in .Net 4.6 will gain "performance and security". This isn't true. If the codebase is identical it will perform identically and the security will be the same.
Each iteration of .Net contains the previous one (it's actually a monolythic process that Microsoft are trying to move away from, hence projects such as Katana)
Each new version of the .NET Framework retains features from the
previous versions and adds new features.
source
Simply upgrading the framework will not magically make you code faster or more secure.
At a previous company we used to do as you are suggesting and ship a .NET 3.5 version (for users on XP) and a .NET 4.0+ (up to 4.5) version.
The way we did this was to have two separate solutions basically called the same and have each of the projects mirrored from the .NET 4.0 version into the 3.5 version. These were actual projects added to the solution.
For the files we simply linked the .NET 4.0 files directly into these projects, but we did have to manually create each folder so that the namespaces matched. For any code that was not supported by .NET 3.5 we had to create an actual file in the 3.5 solution and re-write entirely that feature so that it would compile with 3.5.
This was not fun and actually wasted a lot of development time simply looking after a legacy solution. In the end we migrated everything to .NET 4.5 and expressed to users that we were discontinuing support for the 3.5 version, for us there was not cost for the user to upgrade so it was up to them if they wished to upgrade hardware for new functionality.
In conclusion I would say if you don't need to I would recommend that you don't attempt to support both solutions, it will impact your development time and frustrate developers when they've written this nice feature using the concurrent functionality to then realize this isn't in .NET 3.5 (I know what this is like because I've had it happen).
Based on many articles I have read, I came to the conclusion that it is not guaranteed for a .NET Framework to be 100% backward compatible with the previous versions. So my question is: is it guaranteed for two (or more) versions of the .NET Framework to be installed side by side without any problems (is this documented somewhere by Microsoft)?
For example, can .NET 1.1 be installed side by side with .NET 4.5, or will I have to re-compile my project to work on .NET 4.5?
There's a difference between the Framework version and the runtime version. You can have different runtimes operate side-by-side without interfering if your application is properly marked with the expected runtime in its configuration file.
Programs written for a particular runtime (e.g. 1.1, 2.0, 4.0) can run independently against their given framework with no side effects from the other frameworks. That being said, you must modify your config file to ensure that a .NET 2.0 application runs with the .NET 2.0 CLR when the 4.0 CLR is installed on the machine
The CLR's are affected by the version of the Framework installed on the machine. For example, 4.0 and 4.5 both run with the 4.0 CLR and having 4.5 installed introduces some incompatibilities. That being said, these issues are usually very specific and most applications will not be affected by them.
Here's Microsoft's page on compatibility between Framework versions.
Your question seems to be in two parts:
Are .NET Frameworks backward compatible?
Can you install more than one .NET Framework at the same time on the same computer?
Yes you can install multiple versions of the ".NET Framework" at the same time without problems. Whether or not an app runs as expected is a different story as explained in the MSDN doco.
MSDN:
You can load multiple versions of the .NET Framework on a single computer at the same time. This means that you can install the .NET Framework without having uninstall previous versions Tell me more
...and
In general, you should not uninstall any versions of the .NET Framework that are installed on your computer. There are two reasons for this:
If an application that you use depends on a specific version of the .NET Framework, that application may break if that version is removed.
Some versions of the .NET Framework are in-place updates to earlier versions. For example, the .NET Framework 3.5 is an in-place update to version 2.0, and the .NET Framework 4.5.2 is an in-place update to versions 4, 4.5, and 4.5.1. Golly, tell me more
Backward Compatibility
Though newer versions of the framework are generally backward compatible (with respect to contracts) there may be unforseen behavioural changes visible at runtime.
As MSDN states:
The .NET Framework 4.5 and its point releases are backward-compatible with apps that were built with earlier versions of the .NET Framework. In other words, apps and components built with previous versions will work without modification on the .NET Framework 4.5
...however:
In practice, this compatibility can be broken by seemingly inconsequential changes in the .NET Framework and changes in programming techniques. For example, performance improvements in the .NET Framework 4 can expose a race condition that did not occur on earlier versions. More
So an app without appropriate config may be upscaled to use later versions of libraries leading to undesirable results. Sadly nothing can be done for a 4.0 app if .NET 4.5 is installed because the actual CLR was changed. More...
As Rick Strahl writes:
Note that this in-place replacement is very different from the side by side installs of .NET 2.0 and 3.0/3.5 which all ran on the 2.0 version of the CLR. The two 3.x versions were basically library enhancements on top of the core .NET 2.0 runtime. Both versions ran under the .NET 2.0 runtime which wasn’t changed (other than for security patches and bug fixes) for the whole 3.x cycle. The 4.5 update instead completely replaces the .NET 4.0 runtime and leaves the actual version number set at v4.0.30319. More...
So far, we only see the following frameworks can be run side by side,
.NET 1.x (already obsolete, so don't want to comment more)
.NET 2.0/3.0/3.5 as a whole
.NET 4.0/4.5/4.5.1/4.6 as a whole
.NET Core
And you can see there is no guarantee from Microsoft whether a new version can be installed side by side or be an in-place upgrade of the previous version, and it really depends on what feature sets the new version brings.
We might observe some general rules (such as the frameworks with the same CLR version should be in-place upgrade), but that's still not something guaranteed by Microsoft, and can be broken by a future framework release.
This would be a real pain to try to duplicate, so I'm hoping someone has a quick answer...
Suppose I have a .NET 4.0 application, with a reference to a .NET 2.0 library (SharpZipLib in this case). This of course works fine on a normal machine with .NET 2.0 and 4.0 installed.
If the server running this application has only .NET 4.0 and not 2.0 (or 3.0/3.5 etc.), what do I need to do to allow the .NET 2.0 library to run properly?
From what I've read, it looks like I may be able to put in a config setting for supportedRuntime, but I'm not quite understanding what exactly that does.
Will a config setting work, or would only .NET 4.0 libraries function in this environment?
(This is a hypothetical environment - I don't plan on ever having my own servers with 4.0 and not 2.0, but if someone is crazy enough to do it, I want to be able to support them).
Thanks
The CLR can load older assemblies in the .net 4.0 framework.
Here's a good read:
http://msdn.microsoft.com/en-us/magazine/ee819091.aspx
EDIT: updated quote from article. Particularly notice the bold
The .NET Framework 4 runtime—and all future runtimes—will be able to
run in-process with one another. While we did not back-port this
functionality to older runtimes (1.0 through 3.5), we did make sure
that 4 and beyond will be able to run in-process with any single older
runtime. In other words, you will be able to load 4, 5 and 2.0 in
the same process, but you will not be able to load 1.1 and 2.0 in the
same process. .NET Frameworks 2.0 through 3.5 all run on the 2.0
runtime and so have no conflicts with one another, as shown in Figure
2.
From http://neilblackburn.blogspot.com/2009/10/net-framework-40-backward-compatibility.html (and, transitively, http://mtaulty.com/CommunityServer/blogs/mike_taultys_blog/archive/2009/08/03/installing-net-framework-v4-0-and-running-net-2-0-3-0-3-5-3-5sp1-applications.aspx):
Now, I knew that you can’t just take a 3.5 Service Pack 1 application
and run it on the V4.0 CLR. It needs a V2.0 CLR or reconfiguring with
a <supportedRuntimes/> tag in order to bend the application to run on
the V4.0 CLR and that bending might be something that you don’t want
to do.
From the link in bryanmac's answer (In-Process Side-by-Side):
This means that if an application is recompiled to run against the .NET Framework 4 runtime and still has dependent assemblies built against .NET 2.0, those dependents will load on the .NET 4 runtime as well.
That can mean, however, that there may be bugs due to being run on a different runtime.
If you have the source to SharpZipLib you could just rebuild it as .NET 4.0
Hello friends i need an explanation regarding .NET framework pre-requisite while installing the published application in the target machine.
As java is downward compatible, by which i mean that if i have installed java v1.6 and if the application is developed using java v1.5 (i also mean that only classes and packages available in 1.5 are used to build the appln.)
I am sure that the application developed will definitely run by installing the latest or higher versions of jre or j2se.
Similarly in the case of .NET platform suppose if i develop my application using .NET framework 3.5 and in the target machine i have installed .NET framework 4.0 (the latest) even then it prompts to install the .NET framework 3.5 why is this so?
The real time example is i have downloaded and tried installing MySQL workbench and also installed .NET framework 4.0 But it still asks to install the .NET framework 3.5 before running the MySQL installation.
My question is does .NET framework is downward compatible as java or .NET?
Version Compatibility in the .NET Framework:
The .NET Framework 4 is
backward-compatible with applications
that were built with the .NET
Framework versions 1.1, 2.0, 3.0, and
3.5. In other words, applications and components built with previous
versions of the .NET Framework will
work on the .NET Framework 4.
However, in practice, this
compatibility can be broken by
seemingly inconsequential changes in
the .NET Framework and changes in
programming techniques. For example,
performance improvements in the .NET
Framework 4 can expose a race
condition that did not occur on
earlier versions. Similarly, using a
hard-coded path to .NET Framework
assemblies, performing an equality
comparison with a particular version
of the .NET Framework, and getting the
value of a private field by using
reflection are not backward-compatible
practices. In addition, each version
of the .NET Framework includes bug
fixes and security-related changes
that can affect the compatibility of
some applications and components.
If your application or component does
not work as expected on the .NET
Framework 4, use the following
checklists.
For .NET Framework 2.0, 3.0, and 3.5 applications:
Check .NET Framework 4 Migration
Issues for any changes that might
affect your application and apply the
workaround described.
If you are recompiling existing source
code to run on the .NET Framework 4,
or if you are developing a new version
of an application or component that
targets .NET Framework 4 from an
existing source code base, check
What's Obsolete in the .NET Framework
for obsolete types and members, and
apply the workaround described.
(Previously compiled code will
continue to run against types and
members that have been marked as
obsolete.)
If you determine that a change in the
.NET Framework 4 has broken your
application, check the Runtime
Settings Schema to determine whether
you can use a runtime setting in your
application configuration file to
restore the previous behavior.
If you encounter an issue that is not
documented, file a Microsoft Connect
bug and contact netfxcf#microsoft.com
with the bug number.
Yes, .Net 4 framework is backwards compatible with applications built on previous versions of .Net. You can see this link on MSDN for more info.
If you have .Net 3.5 or .Net 4 installed and a third party still requires either (or and older version) then the installer is not checking the correct prerequisite install conditions.
I'm new in the .NET-world.
I just built my first application with .NET-versionn 4.0 and am wondering if its a wise choice to lower the target-framework as much as possible (to 3.0 maybe) if it still works then.
Whats best-practice when it comes to choosing the appropriate .NET-version?
If you are targeting Windows desktop users, you can be pretty confident they have at least .NET 2.0 and probably higher. It is unlikely they will have .NET 4 though. Unless you know the audience (eg. a business customer), choosing .NET 4 will likely limit your reach at this point.
.NET 4 introduces the first real platform change in a while in that it is built on the CLR (Common Language Runtime) version 4. Before that, .NET 2.0, 3.0, and 3.5 all ran on version 2 of the CLR.
The only difference between .NET 2.0, 3.0, and 3.5 are the in the framework (the libraries). Most of the libraries are unchanged but new libraries where added with each version. It depends what libraries you use. If you include all the libraries you need in your application then you can run anything that .NET 3.5 can do on .NET 2.0.
If you need a legal way of distributing .NET 3.5 era libraries to a .NET 2.0 audience, one option is shipping some assemblies from the Mono Project.
For example, you might find that the only .NET 3.5 assembly you need is System.Core.dll. If you include the Mono version of System.Core.dll with your application, it will run just fine on .NET 2.0 and up even though you are using ".NET 3.5" features (like LINQ for example).
If you are using ASP.NET then it really does not matter what they have as you are just feeding them HTML.
EDIT: I was not aware that Windows Presentation Foundation (WPF) required a service to be running. I have used Mono to add .NET 3.5 features to .NET 2.0 apps but I have not used WPF.
You cannot get the WPF assemblies from anywhere but Microsoft though so you cannot redistribute those anyway. Mono projects tend to use GTK# for the GUI although Windows Forms is also available cross-platform.
Choosing the framework version to support is mainly a question of your target user group.
If you are developing a tool for a
corporate environment, you might be
limited by the framework version that
the default configuration of the
corporation supports (which sometimes
might be a version or two behind the
latest version) - or you are lucky
and the IT department is willing to
upgrade their platform to the latest
version.
If you are targeting home users you
should consider that not everyone is
already having the latest framework
version installed, and not every user
is willing to download and install a
new version just to use your tool. So
you need to consider if you can allow
to ignore such users or not.
Of course, you can always include the latest version with your setup, but don't forget that the framework installation requires administrative rights.