What is the sequence of the Boya Chinese textbooks?
I haven’t heard of this series before, but looking at information from the publisher (Peking University Press) and various booksellers I can see the following:

博雅汉语 = Boya Chinese (1st edition, published around 2004–2009)


初级起步篇I = Elementary starter I
初级起步篇II = Elementary starter II
准中级加速篇I = Pre-intermediate speed up I
准中级加速篇II = Pre-intermediate speed up II
中级冲刺篇I = Intermediate spurt I
中级冲刺篇II = Intermediate spurt II
高级飞翔篇I = Advanced hover I
高级飞翔篇II = Advanced hover II
高级飞翔篇III = Advanced hover III


博雅汉语 = Boya Chinese (2nd edition, published around 2012–2016)


初级起步篇I = Elementary I
初级起步篇II = Elementary II
准中级加速篇I = Quasi-intermediate I
准中级加速篇II = Quasi-intermediate II
中级冲刺篇I = Intermediate I
中级冲刺篇II = Intermediate II
高级飞翔篇I = Advanced I
高级飞翔篇II = Advanced II


In addition to these main textbooks there are various extras, like the Guide books aimed mainly at teachers and Reading and writing giving extra resources.