Older clients are seeing missing December Windowsupdates.
The new version of Software Updater that is currently updating the list of available patches, is not normal behavior that now missing updates are less. Once the database of available software is updated, number of missing updates will increase. Opswat has lower amount of available patches, than ivanti, but they're adding new titles constantly. Basically, new Software Updater database is updating the amount of available patches, database is updating constantly but still lower in numbers compare to old Software Updater, in the following days you should see the number increasing as the patches becomes available.
December updates are also not reported from Client Security 15.10 Clients. Show all important updates are installed. For 14.xx clients missing updates are reported and installed via software updater
F-Secure Client Security 15.10 and later versions use a new Software updater distribution module, which currently does not support Windows 10 feature or service packs. Due to this missing feature, the Windows 10 feature and service pack patches are not be available in the Policy Manager 15.10 Software updater patches list.
The new Software updater engine OPSWAT lacks this functionality, however improvements to return this functionality is expected by Q1/2020.