Can I install just the kernel part of a rollup

Yes you can. It is perfectly acceptable (and supported) to install just the kernel part of a rollup, so you can for example have your application version on 5.0.1000.52 (original SP1) or perhaps 5.0.1500.2985 (rollup 5) and have the kernel version on anything above 5.0.1000.52, such as 5.0.1500.3761 (rollup 6), or maybe something even newer!

I will explain the rules very briefly:

  • We have two different main levels of release: service packs and hotfixes (rollups are just a group of hotfixes).
  • In a service pack release we ARE allowed to have a dependency between the kernel and application builds. This means that you can't mix two different service pack levels or strange things will start to happen in your system.
  • In a hotfix release (rollups are just a group of hotfixes) we ARE NOT allowed to have a dependency between the kernel and application builds. This means you can mix any kernel and application hotfix builds - of course you still need to make sure you're not mixing service packs, so as long as the kernel and application builds you're mixing were both designed to go on top of the same service pack then you're ok.

You might also wonder "What is the difference between a service pack and rollup?", some people may have heard that there is no difference - well that is not strictly true. As you can read above, we've explained one difference - in a service pack there can be a dependency between the kernel and application.

There are also other differences - the really big one is that a service pack release effects supportability - so when a new service pack is released, the old service pack has around 24 months before it falls out of support. This means that if we release service packs too fast we can have a negative effects on our customers, pushing them out of support or forcing them to upgrade when they might not be ready, so we take the decision to release another service pack very seriously.

On the other hand, a rollup is just a collection of normal hotfixes put together in one download (and retested together as one) for convenience. This also gives us a good way to enable customers that want to keep up-to-date with all fixes to do that, without effecting supportability for other customers.


--author: Tariq Bell
--editor: Tariq Bell
--date: 22/02/2011
Comments (9)

  1. Palle Agermark says:

    Thanks for the clarification

  2. Amit says:

    If we install just  kernel part of a rollup , will it make any changes funtionality wise? I do not belive its going to make any changes funtionality wise untill unless we install on application part also? Can you please clarify this?

  3. Jonas says:

    Hi Tariq

    I think I understand this, but still I cannot really figure out how your kernel rollups are supposed to be working.

    I came across a recently published KB article that is called "Kernel Rollup 2292391 (build 5.0.1500.4090) is available for Microsoft Dynamics AX 2009 Service Pack 1" (Article Id = 2292391)

    So I downloaded the hotfix, and the only thing I found in that file was an xpo file. The list of files in the KB Article also contains only a SYP update.

    Are the Kernel rollups not supposed to contain the actual kernel?

    /Jonas Bergman

  4. @Amit – It will not touch your X++ logic, but it can change behaviour of the system in general. So for example it's not going to change where your postings go for some type of journal, but it might change the way that the AOS reads data from the database (just as an imaginary example). Testing is still required, but business logic is not directly modified.


  5. @Jonas – The specific fix you mentioned, 2292391, is a fix to the So it is categorised as a kernel update, but it's not a typical kernel update as the webparts can be deployed in an XPO.

    For latest AX2009 Sp1 kernel as of today you want 2519035, build 5.0.1500.4622, you can get it by contacting us in support.


  6. Andrew says:

    Hi Tariq,

    I discussed this with you briefly at AXUG in Reading last week – you recommended to install the latest Kernel, just dropping it in if we have monthly releases (e.g. with some testing but not to worry about a full regression test of all functions).

    Having re-read the notes, I see that the entire update is called a hotfix rollup, which contains both kernel and application components.

    I assume your recommendation applies only to the "cumulative kernel update", not also to the "cumulative application update" (which would alter the GLP and SYP layers). Or can these be treated in a similar manner? (I doubt it, but you never know).

    Finally, just to double check that there is no way to unbundle a "cumulative application update" in order to extract a specific hotfix(es).



  7. Hi Andrew, yes that's right, it only applies to the kernel part – installing the application part would mean merging all of your X++ customisations, so you'd then have to go and test all of those. For each rollup there is a version released which contains only the kernel part and one which contains kernel and application parts. I believe you can install just the kernel part with either one just by delselecting the application part when you install.

    You can't really extract individual fixes from the rollup – for the kernel part there is literally no way to change it (it's a closed box) for the application part – we release individual fixes for each of the fixes in the rollup, so if ther are specific ones you need then it's possible to get them – bear in mind that some individual fixes might rely on other fixes – so you want one fix, but you have to take 5 because they depend on one another.


  8. Hi Tariq,

    I need to install the client updates of rollup 7 on citrix server for testing purpose and we use the same client for UAT and Live as well. what is the correct approach to update the client in that server?



  9. Hi Ashish,

    The supported approach would be to have separate client machines (separate citrix servers in your case) for each client version that you need to run – we don't have anything built in to allow multiple client versions to run side-by-side.

    I realise this isn't always practical, there is an unsupported approach – that is to simply copy the client folder, for example:

    C:program files(x86)Microsoft Dynamics AX50client

    I can copy that folder, to keep an instance of the current client version then install the new one to the default folder so that I have:

    C:program files(x86)Microsoft Dynamics AX50client_RU5

    C:program files(x86)Microsoft Dynamics AX50client_RU6

    C:program files(x86)Microsoft Dynamics AX50client

    Then I just use shortcuts to the different versions depending on which one I need:

    C:program files(x86)Microsoft Dynamics AX50client_RU6binax32.exe


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