This probably applies to previous versions of Mingle and other Java related products and projects but don't quote me on that.

FAO ThoughtWorks, I think a Goolgle search box would be a valuable addition to your global navigation. I wasted a lot of time looking for answers, and had to result to an advanced Google search to find useful results. Here is an example search.
Furthermore, the 3.5.1 help docs seem to be missing anything to do with SSL (when I use the top right search box). 

What you need to know before reading further aka. prerequisites:

• Know where your Mingle config is.
• Know how to start and stop your Mingle instance.
• Be familiar with working on a command line.
• Familiarisation with Java's keytool.
• Know what OpenSSL is and be faimilar with the openssl cli tool.

Attached is my config from a Debian squeeze instance.

(This assumes your SSL provider wants >=2048 bit RSA CSR) 

1. $ keytool -genkey -keyalg RSA -keysize 2048 -keystore thedomain.com.keystore -alias thealias
2. $ keytool -keyalg RSA -keystore thedomain.com.keystore -alias thealias -certreq -file thedomain.com.csr
   
   Then when the you get the cert back from the CA:
    
3. $ keytool -importcert -trustcacerts -keystore thedomain.com.keystore -alias thealias -file thedomain.com.crt
   

Hi all

With our Mingle 3.0 release we have added even more "official" Mingle Tips and Tricks to our help. Check out our growing list of helpful hints. And of course, don't forget to share your own tips and tricks here on the community.

Thanks Suzie

For the most part, migrating a Mingle 2.3 project to Mingle 3.0 is simple and automatic. You can export the project from the Mingle 2.3 server and import it to a Mingle 3 server. Or you can upgrade your Mingle 2.3 server to Mingle 3 (after you back up per the instructions, of course.) Either way, Mingle will convert your Mingle 2.3 structure to Mingle 3.0 automatically.

I have discovered a few small exceptions that must be fixed by hand. They are:

(1) New Reserved words

Mingle 3 adds new reserved words/phrases, namely 'Created On', 'Modified On' and 'Project". Essentially, these are new built-in properties on every card. If your projects have any properties (including tree properties) that conflicts with one of these, that property name will be changed. If you have a property called 'Created On' it will be renamed 'Created On_1'.

Note that while the property name will change any MQL queries in your reports are not automatically changed to reflect the new name.

(2) Stricter behavior of some charting properties

The data-series chart has many properties, including x-labels-start and x-labels-end. In previous versions of Mingle it was possible to also use x-label-start and x-label-end. This behavior was not documented and should have caused an error. So if you used x-label-start/end you data series chart probably won't look correct in Mingle 3. Add an 's' to each property name and you should be good to go.

(3) The Mingle API

If you have developed any integrations that use Mingle's RESTful API you will have to make at least one small change for your code to work with Mingle 3.0. That change is documented here.

--Matt Quagliana | ThoughtWorks Studios