It is possible to migrate a legacy application to the cloud and support both offline and online usage. One approach to achieve this is by using a hybrid cloud architecture, where the application runs on a virtual machine (VM) in the cloud and the database is synchronized between the cloud and the client's local environment.
To enable offline usage, you can use a local database on the client's device that is synchronized with the cloud database when an internet connection is available. When the user is offline, the application can use the local database to store and retrieve data. When the user is online, the application can synchronize the local database with the cloud database to ensure that the data is up to date.
It's important to note that this approach requires careful planning and implementation to ensure that the synchronization process is reliable and secure. Additionally, the performance of the application may be impacted by the synchronization process, so it's important to optimize the synchronization process to minimize any impact on the user experience.
Overall, migrating a legacy application to the cloud and supporting both offline and online usage is possible, but it requires careful planning and implementation to ensure that the application meets the requirements of the users and the business.