This is a very abrupt change with very little time to widely notify the customer base. The OWA app has lacked in some features such as the ability to add attachments and such, but it was certainly lyuseful in managing shared / delegates mailboxes and multi-calendar management. The app should not be deprecated, but as with everything suggested to Microsoft for the past 2 years, this suggestion will no doubt be ignored. Using a web browser on a phone is just not sustainable, so we’re left with the Outllok app or the native mail app (which is horrible for those with a need to monitor multiple mailboxes and / or calendars).
Bottom line, deprecating the OWA app this soon is a HORRIBLE idea and I can hardly wait for the flood of phone calls from angry clients that I’m sure to get from this sudden removal of an app that has helped them gain a significant boost to their daily productivity and flexibility from a simple act as not having to be toes to their computer or having to have several mailboxes set up on their device.