正版 (zhèng bǎn) is a noun meaning 'licensed/original version' — it specifically refers to officially authorized copies of software, media, or books, as opposed to pirated ones (盗版). It is narrower than the adjective 合法 (hé fǎ, 'legal, lawful'), which describes general legality, and 法定 (fǎ dìng, 'statutory'), which means prescribed by law. Use 正版 when talking about the authenticity of a product copy.