Upgrading p5-app-ack fails for me.

[Barrie Stott]

'port outgraded' showed that p5-app-ack and p5.14-app-ack (but no other *-app-ack) needed to be upgraded and p5.14-app-ack did so without a hitch.

The ports I have  of the form p5* are:
  p5-app-ack @1.940.0_2 (active)
  p5.12-file-next @1.20.0_2
  p5.12-locale-gettext @1.50.0_6+universal (active)
  p5.14-app-ack @1.940.0_2
  p5.14-app-ack @1.960.0_0 (active)
  p5.14-file-next @1.20.0_2 (active)

'port info p5-app-ack' shows the following where the line of particular interest is 'Replaced by: p5.14-app-ack'
  p5-app-ack @1.960.0 (perl)
  Replaced by:          p5.14-app-ack
  Sub-ports:            p5.8-app-ack, p5.10-app-ack, p5.12-app-ack, p5.14-app-ack

  Description:          ack is a tool like grep, aimed at programmers with large  trees of heterogeneous
                      source code.
  Homepage:             http://betterthangrep.com/

  Library Dependencies: p5.14-app-ack
  Platforms:            darwin
  License:              unknown
  Maintainers:          mschout at gkg.net, openmaintainer at macports.org

'sudo port upgrade p5-app-ack' gives (note 1st line):
  --->  p5-app-ack is replaced by p5.12-app-ack
  --->  Computing dependencies for p5.12-app-ack
  --->  Dependencies to be installed: p5.12-file-next
  --->  Activating p5.12-file-next @1.20.0_2
  Error: Target org.macports.activate returned: Image error:  /opt/local/share/man/man3/File::Next.3pm.gz is being used by the active p5.14- file-next port.  Please deactivate this port first, or use 'port -f activate p5.12- file-next' to force the activation.
  Error: Failed to install p5.12-file-next
  Log for p5.12-file-next is at:  /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_ports_perl_p5-file-next/p5.12-file-next/main.log
  Error: The following dependencies were not installed: p5.12-file-next
  Error: Unable to upgrade port: 1
  To report a bug, see <http://guide.macports.org/#project.tickets>

1. Which port is p5-app-ack 'replaced by'?
2. How can I tell if is is safe to replace all my p5.12-* ports by the corresponding p5.14-* ports?
3. Most importantly, how can I upgrade p5-app-ack?

Barrie.