<b>Andre Guirard’s answer:</b>
All versions of Lotus Notes support applications developed in earlier versions. Upgrading your Domino server and Notes clients to a later version will not break your application, and you will get the benefits of improvements in performance, administration, reliability, and email user interface, as well as opportunities to extend your applications using new features, should you choose. This is the path of least resistance for doing an upgrade to a Notes application, and IBM is committed to continuing to support earlier versions of applications as we go forward, so you should always be able to upgrade without reworking your existing applications.
Not all applications are a good fit for Lotus Notes, but for applications of the type that made sense to do with Notes in 5.0, Notes is still the best choice I know of.
I’m not sure what do you you mean by “migrated to a latest technology”…
I’m assuming you’re looking for a different platform / development environment than Lotus Notes.
The answer depends on the type of application you want to develop (client / server – distributed – web…) as well as the number of customers accessing the application, your developers skill set, what the application is supposed to do (the solution for you might be to purchase a software too), …
In general, Microsoft Visual Studio is a pretty flexible solution (languages for development would be VB, C#, J# or C++) as well as Eclipse (language would be Java). For database, SQL server or mySQL are pretty popular.
Hope this helps,