In the bottom of bar 8, they substituted the ♭III7 chord. Additionally, they substituted the V9 chord in bar 10 with a IVmin7 and the one in bar 12 with a V aug.
In bar 8, they changed the ♭III7 chord to another one.  Bars 10 and 12 saw substitutions of the V9 chord with a IVmin7 and a V augmented chord, respectively.