The update.thvs is the file that tupdate may use to make your stored tsid
collection to be in sync with HVSC upgrade.
Unfortunately, is not possible to have all the information needed to update
the tsid tree from the update.hvs file from HVSC update, so I must provide
this custom file after each HVSC update (I hope to give this file in one/two
days after a release of HVSC upgrade, but to build this file is needed some
comparison operation to see how some subtunes are chenged from previous
collection).


THVS file structure:

VER x                                         : version of tsid library needed
FROM x.x y                                    : from x.x hvsc version, update y
TO k.k z                                      : to k.k hvsc version, update z


MOVD path1 path2                              : move directories (not subdir) 
MOVE path1/file.sidt path2                    : move file to directory *
MOVE path1/file1.sidt path2/file2.sidt        : move file and change name (path1 may be path2)
DELETE path                                   : delete a path *
DELETE path/file                              : delete a file in path
SHIFT path/file n #k                          : shift songs by n from song k
GOES path1/file1.sidt path2/files2.sidt #a #b : song a of file1 goes to song 2 of files
SWAP path/file.sidt #n #m                     : swap tune n with tune m
% comment                                     : comment line

VER must be in the 1° line
FROM must be in the 2° line
TO must be in the 3° line
the spaces are significative.
*= not yet implemented