Simplify the following text for a Grade 6 native English-speaking person.
Original: The initial releases were successively numbered as `` previews '' : p5 , p7 , p8 up to p81a , then p9 , p91 , p92 , and p93 .
Simplified: The initial releases were successively numbered as `` previews '' i.e. p5 , p7 , p8 up to p81a , then p9 , p91 , p92 .