Libtool

I got error message about libtool with portupgrade. Can i remove two 
older versions to get rid of it? /usr/ports/devel/libtool14 seem to be 
removed, should there be something about this in /usr/ports/UPDATING?

portupgrade error message:
--->  Cleaning out obsolete shared libraries
[Updating the pkgdb <format:bdb1_btree> in /var/db/pkg ... - 76 packages 
found (-0 +1) . done]
** Listing the failed packages (*:skipped / !:failed)
        ! devel/libtool14 (libtool-1.4.3_3)     (invalid package name)
--->  Packages processed: 1 done, 74 ignored, 0 skipped and 1 failed

# pkg_info | grep libtool
libtool-1.3.5_2     Generic shared library support script (version 1.3)
libtool-1.4.3_3     Generic shared library support script (version 1.4)
libtool-1.5.6_1     Generic shared library support script (version 1.5)

5.2.1-RELEASE-p3