Can you build one add-in for multiple versions of Office?

re: Can you build one add-in for multiple versions of Office?

andreww — Fri, 12 Jun 2009 21:06:00 GMT

Anurag - not, Office does not support versioned add-in installs. Office will pick up all registered add-ins, regardless of version.

re: Can you build one add-in for multiple versions of Office?

Anurag Aggarwal — Fri, 12 Jun 2009 15:13:35 GMT

Is it possible to install seperate add-ins dlls , one for 2003 and another for 2007 on a a machine where only office 2003 is available so as when user upgrade to office 2007 it picks up add-in related to 2007?

Thanks

Anurag

re: Can you build one add-in for multiple versions of Office?

Mike McMack — Wed, 27 May 2009 22:36:20 GMT

Andrew,

Thanks, that did it!

re: Can you build one add-in for multiple versions of Office?

andreww — Wed, 27 May 2009 21:38:26 GMT

Mike - it sounds like the add-in is hard-disabled. The list of hard-disabled add-ins is app-specific, version-specific and user-specific. For example, the list for Excel 2007 is kept in the registry here: [HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Excel\Resiliency\DisabledItems].

To check/re-enable a hard-disabled add-in, go to the Trust Center, Add-ins, and drop down the Manage listbox to find the Disabled items.

re: Can you build one add-in for multiple versions of Office?

Mike McMack — Wed, 27 May 2009 20:27:16 GMT

Hi Andrew,

As luck would have it, the add-in stopped loading in Excel 2007 on one machine. We didn't make any changes to the add_in, its still an office 2003 COM addin (built in C# with Dev Studio 2008 + SP1) it loads in Excel 2003 on that same machine. We've tried everythying, uninstalling/reinstalled the add-in, excel 2007, the PIA's. When Excel starts, the COM add-in is listed in the Excel configuration tab, but its listed as disabled. We check the checkbox, restart, it doesnt load and its still disabled. We checked the loadBehavior registry key, its correct, set to 3, never changes. We checked the trust center, nothing bad there. Any suggestions greatly appreciated.

Mike

re: Can you build one add-in for multiple versions of Office?

andreww — Sat, 23 May 2009 00:36:45 GMT

Mike - if you're building on a machine with Office 2003, I assume you're only using 2003 features. Later versions of Office are generally supersets - that is they don't generally remove features, but simply add more features. So any 2003 features should all still be present and correct in 2007. Which means, you don't need the 2003 PIAs on the 2007 machine, as the 2007 PIAs should be a superset of the 2003 PIAs.

re: Can you build one add-in for multiple versions of Office?

Mike McMack — Sat, 23 May 2009 00:29:26 GMT

Thanks Andrew. Great article as usual.

I just wanted to clarify one thing: If the add-in is developed/built on a build machine with Office 2003 PIA's, does that mean that Office 2003 PIA's need to be installed on the deployment machine, even if the customer is using Office 2007?

re: Can you build one add-in for multiple versions of Office?

andreww — Fri, 22 May 2009 23:00:06 GMT

Mike - I understand that many organizations cannot move on to the latest version in the short term. My point is that in this scenario, you don't have to do anything. Your 2003 add-ins should just work in 2007.

You would only want to move on to building 2007 add-ins if your customers moved to 2007 AND if you want to take advantage of new features in 2007.

You only have the problem of targeting multiple versions if your customer has multiple versions deployed AND your add-in needs to work in multiple versions AND you need to do different things depending on which version you're running in. In this scenario, you're targeting the lowest common denominator, but at the same time building in forward compatibility. Fortunately, this is not a common scenario.

Also, just to clarify, this affects all technologies - it doesn't matter if you're using VSTO or not.

re: Can you build one add-in for multiple versions of Office?

Mike McMack — Fri, 22 May 2009 22:43:25 GMT

Dear Andrew,

Thanks for a great post. Regarding:

"So, do you want to keep building 2003 add-ins, even though you're targeting Office 2007? It seems to me, you really want to move on. Office has moved on – 2007 introduced major changes from previous versions. VSTO has also moved on."

It's not our choice. Some large organizations don't update office in a predictable way, so its unfortunately up to development to figure out how to make our product work with multiple versions of office, and have contingency plans in place so that their IT deployment folks don't blow a gasket when they can't install a version.

re: Can you build one add-in for multiple versions of Office?

andreww — Fri, 22 May 2009 22:43:04 GMT

Mike - the technique described in this post is for the case where you want to take advantage of _different_ features available in multiple versions of Office.

If all you want to do is build an add-in for one version, and have that add-in continue to work for later versions - then, you don't have to do anything. Office takes great pains to maintain backwards compatibility, so an add-in built for Office 2003 should just continue to work the same way as always in Office 2007 and later. This has always been the case, since COM add-ins were first introduced in Office 2000.