BUG #14412: Problems upgrading Postgresql

The following bug has been logged on the website:

Bug reference: 14412
Logged by: Harry Clarke
Email address: harry(at)harryclarke(dot)me(dot)uk
PostgreSQL version: 9.6.1
Operating system: Windows 8.1 Pro
Description:

Currently running Postgresql version 9.5.3 with PostGIS 2.2.1 (64 bit)
successfully.
To upgrade to latest version, I performed the following actions
1) ran pg_dumpall of current database
2) Installed Postgresql version 9.6.1
3) Installed Postgis version 2.3.0
4) ran psql on the database with post set to new server which failed after
creating schemas, and a couple of extensions, with message
"psql:db1.out:277: server closed the connection unexpectedly..."

The both servers for 9.5 and 9.6 seem OK using pgAdmin III (on the same
PC)

However, I get problems trying to pgAdmin 4 which is very slow starting, and
has crashed several times.