Some customers are currently using the EWS interface (Exchange Web Services) to sync reservations between Outlook and Axxerion. This is the ‘old’ way of interfacing these reservations, and this is announced end of life by Microsoft as of October 1, 2026 (https://techcommunity.microsoft.com/t5/exchange-team-blog/retirement-of-exchange-web-services-in-exchange-online/ba-p/3924440).
If customers who are currently using EWS, still want to sync reservations between Outlook and Axxerion after this date, they will need to be migrated to the new Exchange Graph integration. To do this, some additional work is required which is documented below.
Since the setup of the new Exchange Graph integration requires one of the two systems (Axxerion or Outlook) to be the initial source of (future) reservations, the other system must be cleared of future reservations (related to resources in Outlook). Since this is most likely not the case if the customer is currently using EWS, the following is needed:
In short:
Make sure there are no future Outlook-related outbound reservations in Axxerion
Disable the EWS interface
Setup the new Exchange Graph integration (using the configuration guides)
Have all the future reservations in Outlook synced to Axxerion again
In more detail:
1: First get an overview of all future, outbound, Outlook-related reservations in Axxerion.
Use report ‘REP-459 (Future, outbound, Outlook related reservations)’ for this (available in the 24.1 release).
These are all the reservations that are created in Axxerion (instead of Outlook), but are synced to Outlook (as only these reservations matter for this migration. A customer might also reserve workplaces or equipment that are not linked to Outlook).
These reservations will need to be deleted (once the EWS interface is turned off, such that they will not be deleted in Outlook) and will be recreated again (based on the Outlook reservation counterpart) during the initial setup of the new Exchange Graph integration.
So the goal is to only have inbound (created in Outlook) future reservations synced to Axxerion related to rooms in Outlook, during the start of the migration.
A first analysis showed that the number of existing future, outbound, Outlook-related reservations for the current list of EWS customers is very limited (between 0 and 200).
2: Decide (together with the customer) on the best course of action to remove these reservations. As there are three options to choose from:
A: Before disabling the EWS interface: Have the requestors delete the reservation in Axxerion and recreate it in Outlook (they will be synced back to Axxerion via the current EWS interface, but this time Outlook is the source).
This will make sure the users can still edit their reservations (in Outlook) themselves and these changes will sync to Axxerion, once the Exchange Graph integration is live.
B: Before disabling the EWS interface: Have one (probably Axxerion admin) user (who also has access to all the resources in Outlook) delete all the reservations in Axxerion and recreate them in Outlook.
This will make sure at least one user can still edit the reservations (in Outlook, instead of Axxerion) if needed (and those changes will sync to Axxerion), but it will not require work from the end users.
C: After disabling the EWS interface: Delete all the reservations in Axxerion and do not recreate them in Outlook.
This will result in nobody being able to edit the reservation anymore (apart from an Outlook admin user since the reservations will all be considered created by the general service account in Outlook (as that is how EWS is set up). But this is the least amount of work.
Which of these options suits best will depend on the client's wishes and the number of future reservations.
To limit the number of (future, outbound, Outlook-related) reservations, it is adviced to (ask to) actively encourage users to already stop using Axxerion to create meeting room reservations and only use Outlook for this for some time before the actual migration starts.
3: Discuss a viable planning for the migration to Graph with the customer (and also discuss the planning with the development integration team, as they have to initially sync the reservations back to Axxerion again for the Graph setup). Pick a date on which the EWS interface can be disabled, reservations in Axxerion will be deleted (based on one of the three options mentioned above), the Graph API can be set up and the development integration team can initial sync the future Outlook reservations back to Axxerion.
4: On the planned date, make sure the customer does not create any (Outlook-related) reservations in Axxerion (otherwise, these will get deleted and not synced to Outlook).
5: Only applicable if option 2A or 2B is chosen, else move to the next step: On the planned date, remove all the future Outlook-related outbound reservations in Axxerion.
6: On the planned date, disable the EWS interface:
7: Only applicable if option 2C is chosen, else move to the next step: On the planned date, remove all the future Outlook-related outbound reservations in Axxerion.
8: Setup the Graph integration. Most steps can probably already be done before this planned date, just make sure not to enable it before this date (the sync is enabled as soon as the recources in Exchange are mapped to the reservables in Axxerion in the Router).
9: Have the development integration team sync the (future) Outlook reservations back to Axxerion (same action for customers that did not use EWS before, but do already use Outlook).