I have Frame Maker 2019 and I received a FM12 book with several FM files to be translated. Which MIF version is the most suitable to be used for translation (MIF 7.0 or MIF 2019)? Moreover, is there a simple way to save all FM files as MIF all at once without installing any external plug-ins?
There is no way to save all the files in a book to a different format without using a plugin of some sort, either a DLL or an ExtendScript. That being said, Adobe still provides the BookMIFWash.dll as an "example" utility, which will do most of what you want since it does not delete the MIF files after performing the wash. Note, however, that it saves ONLY to the most recent MIF format.