Yes, it is true. At this moment Vimalin 2.0 still is a 32 bits application and as a result you might get the scary “Vimalin is not optimized for your computer” warning. This is a warning from apple to indicate that this application will not work on the next version of macOS. It does function just fine even while it is 32 bits.
We have been working on a 64 bits version of Vimalin. However when apple announced that macOS Mojave would still support 32 bits applications it was decided that adding new and improved functionality made more sense to spent for the available time as changing the application with no clear benefit beyond the “it is now 64 bits” statement.
Rest assured that we are committed to release a 64 bits version before the next macOS will be released.