Plazmic question for 8703e

Long time reader first time poster.... I have an 8703e and was wondering what version of Plazmic I needed to start the creatation of my perfect BBtheme... I started one with Plazmic 4.6 but it wouldnt load onto my BB. Then I found Plazmic 4.2.... My 8703e is running OS v4.2.1.110... Thanks to anyone who can help or point me to the appropriate place for help!!! One additional question??? This is the latest OS provided thru Verizon (my carrier) Is there a newer OS my 8703e will support? You guys rock, again, thanks!