This download contains TinyMCE 4.5.7 for CMSimple 4.6 and higher, optimized for CMSimple 4.7 and higher.
Download TinyMCE 4.5.7 »
(ca. 420 kByte zip - 2017-04-29)
You simply can upload the folder tinymce/ with all its folders and files to the folder ./plugins/, all files will be overwritten.
But the better way is to delete the old tinymce plugin completely, so that not needed old files are removed.