There is only one (yes, one) valid reason for staying on Dynamics 365 Finance and Operations v7.3. And that is if you have any open extensibility requests with Microsoft.

Your extensibility request is communicated directly to the Microsoft Dynamics 365 development team to ask for access to hook into a specific piece of standard functionality. And you only do this when a customisation requirement can’t be handled in any other way.

The reasons to move to v8.1 list is way more appealing though. And longer.

1. Go SaaS. When you upgrade to 8.1 you get a true SaaS solution. So think lower costs, more flexibility and unlimited scalability.
   
   
2. Service you can count on. Minimal downtime with 99.5% availability per month of service.
   
   
3. All the toys. Latest supporting technologies including Azure Active Directory, Azure SQL, PowerBI, PowerApps, and CDS.
   
   
4. Stay up with the play. Benefit from latest features as they come out. And immediate use of 8.1’s newest features which are detailed in the release notes available at https://docs.microsoft.com/en-us/business-applications-release-notes/October18/index
   
   
5. Help when you need it. Full support from Microsoft.
   
   
6. Full range of App Source ISV options.

The upshot? There’s not much to be said for staying put on v7.3.

In just 4-6 weeks¹ we can get you upgraded to Dynamics 365 Finance and Operations v8.1 and looking good.

So why wait?

^{1 Timeframe depends on a number of factors, any existing code overlayering will require additional time to move to extensions.}