propellor 2.15.0 released with [[!toggle text="these changes"]]
[[!toggleable text="""
   * Added UncheckedProperty type, along with unchecked to indicate a
     Property needs its result checked, and checkResult and changesFile
     to check for changes.
   * Properties that run an arbitrary command, such as cmdProperty
     and scriptProperty are converted to use UncheckedProperty, since
     they cannot tell on their own if the command truely made a change or not.
     (API Change)
     Transition guide:
     - When GHC complains about an UncheckedProperty, add:
     	`assume` MadeChange
       (Since these properties used to always return MadeChange, that
       change is always safe to make.)
     - Or, if you know that the command should modifiy a file, use:
     	`changesFile` filename
   * The `trivial` combinator has been removed. (API change)
     Instead, use:
     	`assume` NoChange
     Or, better, use changesFile or checkResult to accurately report
     when a property makes a change.
   * A few properties have had their Result improved, for example
     Apt.buldDep and Apt.autoRemove now check if a change was made or not.
   * User.hasDesktopGroups changed to avoid trying to add the user to
     groups that don't exist.
   * Added Postfix.saslPasswdSet.
   * Added Propellor.Property.Locale.
     Thanks, Sean Whitton.
   * Added Propellor.Property.Fail2Ban."""]]