Upgrade failing 19.1 to 19.7

[OnYourMarks]

Hi,

I'm behind on my upgrades and want to get to the latest stable 20.1.X release.

Current setup is:
OPNsense 19.1.10_1-amd64
FreeBSD 11.2-RELEASE-p11-HBSD
OpenSSL 1.0.2s 28 May 2019

on an apu2 box.

I unlock 19.7 and start update. Then I get the following.

***GOT REQUEST TO UPGRADE: all***
Updating OPNsense repository catalogue...
OPNsense repository is up to date.
All repositories are up to date.
Updating OPNsense repository catalogue...
OPNsense repository is up to date.
All repositories are up to date.
Checking for upgrades (14 candidates): .......... done
Processing candidates (14 candidates): . done
Checking integrity... done (1 conflicting)
  - squid3-3.5.28_2 conflicts with squid-4.7_2 on /usr/local/etc/rc.d/squid
Checking integrity... done (0 conflicting)
The following 2 package(s) will be affected (of 0 checked):

Installed packages to be REMOVED:
   opnsense-19.1.10_1

Installed packages to be REINSTALLED:
   flowd-0.9.1_3 (options changed)

Number of packages to be removed: 1
Number of packages to be reinstalled: 1

The operation will free 25 MiB.
pkg-static: Cannot delete vital package: opnsense!
pkg-static: If you are sure you want to remove opnsense,
pkg-static: unset the 'vital' flag with: pkg set -v 0 opnsense
Starting web GUI...done.
Generating RRD graphs...done.
***DONE***

Any help with what I can do to fix this (other than a complete install from scratch) would be great.