[Koha] How often do upgrades happen to Koha?

One final question... on average, how frequently is Koha updated (so I can determine support requirements if we have to move to Red Hat as opposed to Debian)? It looks from the schedule I see that every month there is an update. Is that true? As we mentioned in previous thread, our Corporate IT support will only support Red Hat so if I only need to update every 6 months or over, then that would be fine to have them support for that long interval. We are also looking at a hosted solution.... Thanks again for your time and patience! David W. Hartman