Actually I enjoyed Apple offer (strategy) for upgrades of o.s. if the from-version and to-version are not adjacent versions. Direct upgrade supported (even recommended) and only that possible if installers for intermediate versions are not available - this way seemed for me to be less costly as with stops on intermediate stations. Addressed are here upgrades of major versions, e.g. El Capitan to Sierra. In case here it was from Mavericks to Sierra. Having the upgrade completed, fresh after completion I am no more sure if it was the optimal journey flow as Apple stock apps like to change formats of data handled and stored by them on change of o.s. major version increase. The longer distance between from-version and to-version on o.s. upgrade the more data format changes might had happen on this distance. It is always easier to make single conversion than to chain such conversions. Risk of errors is higher on chaining format conversions. So with my upgrade 10.9 to 10.12 I experienced several problems regarding Apple stock apps - some are addressed here on MacRumors forum. I wonder if the outcome would been better if I had make journey from Mavericks to Sierra with stops on every (or some) intermediate station(s). Anybody likes to share own opinion? Your input is welcome. P.S. However this was only option for me as I missed the opportunity to download Yosemite or/and Capitan installers. Got informed those days it was not possible to break the process between installer download completion and o.s. install/upgrade process but no plan had compiled how to handle all my backups on upgrade. My fault to not had invested time into matters of installers availability. Got informed also those days direct upgrade to distant major version was not supported.