Bug reports are extracted from the NEWS file
  of the specified package.
  Only those after a specified date, or after a specified version
  of the package, are retained.
  The bug reports are then sorted alphabetically, so that all bugs affecting a
  particular function are listed consecutively. Finally the table of bug
  reports is displayed (if show=TRUE) and returned invisibly.
  
The argument sinceversion should be a character string
  like "1.2-3". The default is the current installed version of the
  package.
The argument sincedate should be a 
  character string like "2015-05-27", or a date-time object.
If sinceversion="all" or sincedate="all"
  then all recorded bugs will be listed.
  
If package="spatstat" (the default) then
  sinceversion="book" and sincedate="book"
  are interpreted to mean sinceversion="1.42-1",
  which gives all bugs reported after publication of
  the book by Baddeley, Rubak and Turner (2015).
Typing bugfixes without parentheses will display a table of
  all bugs that were fixed in the current installed version of spatstat.