IBM Mainframe Forum

Hello,

Could some one tell me why IBM releases the ZOS versions in the odd number releases, like ZOS 1.7, 1.9, 1.11, etc. ? Is there some logic behind it ?

I would suggest You review Your counting/numbering skills
from
http://www-03.ibm.com/systems/z/os/zos/ ... index.html

z/OS elements and features publications
Book 1.12 |1.11 | 1.10 | 1.9 | 1.8 | 1.7 | 1.6 | 1.5 | 1.4 | 1.3 | 1.2 |
PDF 1.12 | 1.11 | 1.10 | 1.9 | 1.8 | 1.7 | 1.6 | 1.5 | 1.4 | 1.3 | 1.2 |

no evidence that the even <things> were skipped

enrico-sorichetti is correct. For some reason big JES2 changes seem to happen in even numbered z/OS releases. Another useful rule of thumb is the first dot release seems to be a rehash of the last release of the predecessor. For example, z/OS Version 1.1 had nothing that wasn't in OS/390 2.10, and this has been true for quite a long time.