Long term VSTO addin's support roadmap for MS Outlook

Question

The New Outlook announced recently says it does not support VSTO add-in's (visit https://techcommunity.microsoft.com/t5/outlook-blog/things-to-know-about-the-new-outlook-for-windows/ba-p/3383964). Users wanting support for VSTO addin's are being advised to use classic Outlook. Is there any indication in terms of how long classic Outlook will be supported alongside New Outlook?

Also, is this setting a pattern for things to come? e.g. Might there be a version of New Word, New Excel on the horizon that will not support COM/VSTO add-ins and will have classic apps as counterparts?

There will be organisations similar to ours who have invested heavily in feature rich VSTO add-in's that cannot easily be ported across as web add-ins due to the feature gaps between the two stacks. It would be good to have an idea of what the roadmap looks like for COM/VSTO add-ins so organisations can plan accordingly.

Answer 1

Our company develops Outlook Time Tracking systems and we also use plugins for Outlook using VSTO.

However, we came to the conclusion many years ago that with 7 versions of Outlook, Microsoft might one day view this to be unsustainable and rationalize their product line. We believed they would remove the Mac and PC desktop versions and replace them with local "shell" apps that run OWA, which appears to be exactly what has happened. We decided at that time to evolve our product to not need plugins. With some lateral thinking, some AI and a lot of elbow grease, we redesigned our systems to be able to work without plugins, but still work within Outlook and provide customers the same functionality.

When Microsoft announced project Monarch in 2021, we knew we had made the right choice and doubled down on our choice and added new features to automate time tracking, work with Teams and other systems to effectively create a Microsoft time tracking suite which was even better than our plugin version.

Although the loss of VSTO may appear as a sad day for end users, the security concerns are understandable. The fact that we have been able to re-engineer our solutions to provide the same functionality to our customers with a different approach I hope helps others reading this post to carry and find a way forward for your products. Our view is that this will happen to all Microsoft Office products, so if you rely on plugins, don't panic, you still have time as yoru customers will still use Classic Office products for a year or two. This should give you enough time to re-engineer your solutions.