Little problem upgrading to minimserver 2.1 on Synology D216j - DSM 7

[Dragon77]

Having been a long time happy minimserver 1 user (many thanks Simon), I have finally followed the detailed instructions, and started updating my installation to 2. So far:

Installed minimwatch 2 on my PC
Java 8 removed
Synology D216J DSM OS from 6 to 7
Repaired minimserver on the NAS

Package Centre now tells me that I have 2.0.18-2003 installed.

All is running and working well but I believe I should be able to upgrade to version 2.1 but I cannot install IAW the instuctions.

I do not have an update button against minimserver in the installed section, minimserver 2.1 does not show in the available packages.

So I downloaded MinimServer-2.1-2100-armv7.spk (for Arm 7 I believe) in order to manually install, but my Package Centre settings do not have an option to change the trust settings. I have 'general', 'auto-update' and 'package sources', but not 'certificate'. I did try to add minimworld/https://minimworld.com in the package sources but it says invalid location.

If I select manual install and select the .spk file I get a grave warning about the evil that Simon Nash products wreak upon the world, but there is an agree and continue button - is it OK to do it this way?

I would prefer to have it all as described with the trust settings. But I have probably made an error somewhere...