Is it mandatory to upgrade to the newest version available. am not able start a new blank app with 7.23.3 as it is expecting 7.23.4. Please clarify.
Actually, I tried it from the 7.23.3 modeler, and Karthigaiselvi Paulraj is right. When trying to start from Blank App, you are prompted to start from 7.23.4
However, when I tried version 7.13.1 it works fine.
It could be that Mendix fixed a certain issue in 7.23.3 and from now on don't want you to start a Blank App from this version.
You do not need to upgrade. However, you can only work in the version that your modeler is at. So if you open an existing older project in a 7.23.4 modeler, the modeler will upgrade the project to 7.23.4. The same goes for starting a new project.
However, you are free to download the 7.23.3 modeler version and start a new blank app with 7.23.3
No, you can start a new project in any available version of the modeler. However, the New App / Edit App button in the mendix.com environment often wants to start in the newest version of the modeler.
If you want to start a project in a specific version of the modeler, it's easiest to create that project from the modeler.