Updated versions often fix missing characters (grantha letters) and improve ligature rendering.
The original versions of popular fonts like MCL Valluvan were often encoded in legacy standards (like TTF format tailored for specific keyboard layouts). They struggled with the modern Unicode standard, which is the universal character set that allows text to be read across all devices and platforms without "box" characters appearing. mcl valluvan font download upd
Because MCL Valluvan is a non-Unicode font (like Bamini), you cannot simply type with a standard Tamil keyboard layout. mcl valluvan font download upd