What does this error message mean?

[Paul Beard]

pkg-static: Warning: @exec is deprecated, please use @[pre|post][un]exec

Additional context: 

====> Compressing man pages (compress-man)
===>   Installing ldconfig configuration file
--->  Build of net/qt5-network ended at: Mon, 24 Dec 2018 22:06:29 -0800 (consumed 00:05:03)
--->  Updating dependency info
--->  Uninstallation of qt5-network-5.12.0_1 started at: Mon, 24 Dec 2018 22:06:29 -0800
--->  Fixing up dependencies before creating a package
--->  Backing up the old version
--->  Uninstalling the old version
[Reading data from pkg(8) ... - 550 packages found - done]
--->  Deinstalling 'qt5-network-5.12.0_1'
--->  Preserving /usr/local/lib/qt5/libQt5Network.so.5 as /usr/local/lib/compat/pkg/libQt5Network.so.5
cp: symlink: libQt5Network.so.5.12.0: File exists
Copy failed!
[Reading data from pkg(8) ... - 550 packages found - done]
** Listing the failed packages (-:ignored / *:skipped / !:failed)
        ! qt5-network-5.12.0_1  (copy failed)
--->  Uninstallation of qt5-network-5.12.0_1 ended at: Mon, 24 Dec 2018 22:06:31 -0800 (consumed 00:00:02)
--->  Upgrade of net/qt5-network ended at: Mon, 24 Dec 2018 22:06:31 -0800 (consumed 00:05:06)
--->  ** Upgrade tasks 1: 0 done, 0 ignored, 0 skipped and 1 failed
--->  Listing the results (+:done / -:ignored / *:skipped / !:failed)
        ! net/qt5-network (qt5-network-5.12.0_1)        (uninstall error)


cd /usr/ports/net/qt5-network 
[root at www /usr/ports/net/qt5-network]# make deinstall reinstall 
===>  Deinstalling for qt5-network
===>   Deinstalling qt5-network-5.12.0_1
Updating database digests format: 100%
Checking integrity... done (0 conflicting)
Deinstallation has been requested for the following 1 packages (of 0 packages in the universe):

Installed packages to be REMOVED:
        qt5-network-5.12.0_1

Number of packages to be removed: 1

The operation will free 2 MiB.
[1/1] Deinstalling qt5-network-5.12.0_1...
[1/1] Deleting files for qt5-network-5.12.0_1: 100%
===>  Installing for qt5-network-5.12.0_2
===>   Registering installation for qt5-network-5.12.0_2
pkg-static: Warning: @exec is deprecated, please use @[pre|post][un]exec
Installing qt5-network-5.12.0_2...