After several years, Google has finally revamped the build number format in the recently released non-preview version of Android 8.0 aka 'Android Oreo'. Unlike the previous pattern of using two sets of three letter sequences in its Android firmware build numbers, Google has just adopted the split-numbering system with three blocks of numbers and letters separated by periods.
According to a recent blog post on Google's Android developer portal, Android Oreo and later versions will have the following build number format: "PVBB.YYMMDD.bbb".
The 'P' part represents platform release such as 'O' in Oreo. The 'V' stands for supported vertical, which relates to the 'P' that represents the primary platform branch. Finally, the 'BB' part points to an alphanumeric code which represents the exact code branch used in the build.
According to Android Police, the first Oreo release on the Pixel phone is denoted as 'R6' in the build number 'OPR6.170623.012'.
The central code block of the build number reads 'YYMMDD' and it translates to the date format (year, month and day) when the release was branched or synced with the development branch. This is definitely not the build date as it is common to use the same date code for subsequent incremental builds over any major Android release. The 'bbb' set of characters will only help identify a particular build with the same date code.