I tried searching the forum, but the only comments I found directly relating to this subject are the discussions I had with other people when discussing another matter.
Having anything auto-update without my knowledge, whatever it may be, is completely unacceptable and a serious threat to my system stability in my opinion so before I can start using extensions, I need to know how how they update and if they indeed do auto-update(if what I saw in a description of one of them is accurate), then I need to know how to disable this and how I can update them manually once it's disabled.
Since it's also possible to use chrome extensions in addition to the opera ones, I need to know if the update behavior is linked between the two and if it's not, then how to achieve what I need for both of them.
Edit: I forgot to specify that this is about opera v20 if it wasn't obvious enough.
As long as I remember, when an update is available, Opera displays a notification with a button that can take you to the Update section in Extensions, where you can choose to update it or not.
Well, I found this doing a standard search, which I found quite an interesting read (though not too sure if it's still relevant today (8 months later)). I could not locate the post from a developer on The Opera Developers Blog that one of the people linked to in that topic (as the link now points to the main Opera Dev blog page}, Though they apparently answered their question.
Hope someone chimes in with some concrete info to your query, as I'd be quite interested in the answer too.
There is apparently no official way of disabling automatic updates. There is, however, something called an Update Freezer, which seems to stop automatic updates. it goes back to Opera 15. You may not get security updates, but if you're willing to put energy in advance to finding out what is in the update, this approach may help, is at least, perhaps, worth looking at. Not sure though if this is limited to the Opera program, or includes extensions. If it just relates to the Opera, it is still something -- I'm not sure if you were aware of it. Also is it limited to opera 15. Don't know.
After reading what it does, it seems that the extensions indeed do get updated automatically, even in v20. Not sure if they are silent too, but they very likely are.
All it does is change the value inside the preferences file from the config folder for the next time opera should look for extensions updates by setting it to a couple of years from now which basically disable updating.
The value to change is located under the extensions section, under autoupdate and looks like this:
I can't seem to remember how time written like this is called though so I'm not sure how to convert it into something readable.