@namtranduc I am using Opera Next 24.0

Oh, you posted in a thread which belonged to a Opera 12 problem, therefore i did not know you're using Opera 24. Next time, please add some information about your Opera version.

I am using Opera Next 24.0, after I press Alt P I don't see button "Advanced Security". what is wrong to me?

Those options are for Opera 12.17 and older.

Close Opera and empty your %temp% folder to try to get rid of that message.

I just don't like the idea of them constantly writing new browsers now for every new version. I have to keep 12 on my site now as I have 1000's of sessions that I use to look up previously stored sights. It's sad that they cannot combine the two. maybe in the future they will find a way to do it.

Thanks for the explaination!

and I am not understanding why Opera did such thing.

It's a long story with a few twists and turns. Trying to reduce it to a few sentences will likely give the wrong idea. BUT... it seems that after 17 years of producing a browser suite that never really caught on with the general public, it was decided to rewrite the code and produce a new type of browser from the ground up. Some believe it was a decision made in the boardroom by shareholders demanding a greater return for their investment. Others have told us it was a decision made largely by Opera's developer community. Many had been reassigned and many were let go or voluntarily left the company. The claim was the the older Presto version took up all their time and resources simply trying to keep it compatible with today's websites and the idea of a browser that contained all of its features was no longer desirable. Instead the new browser would be built upon the Chromium model and would be configurable via extensions. There are more twists and turns to this story and I've only presented a thumbnail sketch here.

Can we save all tabs?

Yes, by right clicking any existing tab and selecting 'Save Tabs as Speed Dial Folder'.

so what does it have? Can we save all tabs? I guess I need to download it and try it. I like Opera 12, but it seems like they are not going to extend it's version any longer, so sad, as the sessions things are so good.

Leushino, no problem. Yes, after reading all these things I have come to know that it is a totally different browser, and I am not understanding why Opera did such thing.

Leocg you are right, I am not asking about how to disable it, actually I went to make sure that it was enabled to begin with, which it was.
I have never even heard of Opera having any version past 12 let alone already on 24.

Ah... my mistake. Sorry for assuming the wrong thing and glad you're one of those who want auto-update enabled. The thing is... in v.12 it does not auto-update to Blink so you would not have been informed. The new Opera is an entirely different browser.

Will I be able to transfer my passwords, bookmarks, sessions, skins, etc?

There are no sessions and skins on Opera Blink. It probably will import your passwords nnd bookmarks.

I have never even heard of Opera having any version past 12 let alone already on 24.

It would have been nice if Opera actually informed us about this. I had no idea there were versions after 12 even available. And I assumed, wrongly, that I was using the latest version. Indeed I met a problem just recently that one website did not load at all using 12. I may download 24 but probably only use it if 12 doesn't work.

Will I be able to transfer my passwords, bookmarks, sessions, skins, etc? It seems like maybe not... Can we copy them over by ourselves? or there is no way to do that?

I don't understand why this information isn't provided when you check for updates in 12.17. Seems simple to do (but I'm not a programmer) and the most correct option.

Because they are different products although the name has been kept the same. Opera Presto has features that are not included on Opera Blink and vice-versa.

If they had included the info on update checker, people would have started to upgrade and noticed that their notes, bookmarks and so on were no longer there and i don't think they would like it.

Duplicate of:
https://forums.opera.com/topic/4890/please-add-the-option-to-disable-opera-autoupdate/11:

I don't think they are related. The OP isn't asking for a way to disable autoupdate but asking the reason for not have been notified about Opera Blink releases.

...
I don't understand why this information isn't provided when you check for updates in 12.17. Seems simple to do (but I'm not a programmer) and the most correct option.
I "discovered" the new version almost by accident ...

Perhaps because all those users with automatic updating turned on in 12.17 would continually get the information repeated about the new Opera availability, each time Opera 12.17 auto-checked for updates? Since the new versions don't install on top of or replace the old Presto versions, there would be no way to satisfy the Presto version's update checker - there would always be the newer version available. Opera elected, for good reasons, to maintain both Presto and Blink Opera versions concurrently for a period of time (which is probably fast winding down).

Opera 24 is based on a different "platform", and it seems they are working a lot to make it better. But IMHO there's much to do to reach the older version level.

I don't understand why this information isn't provided when you check for updates in 12.17. Seems simple to do (but I'm not a programmer) and the most correct option.

I "discovered" the new version almost by accident, and I'm working with both (in my case the new installation (v 24) kept unaltered the older one (v 12) and that's good, mostly because the new one don't have (yet, some say) a fine bookmark manager, relying on third-party "Extensions")

https://forums.opera.com/topic/4890/please-add-the-option-to-disable-opera-autoupdate/11:

I could not load a website on 12 and complained to the company, they in turn told me my browser is out of date. Which doesn't seem accurate either, as 12.17 is the only one of the new 7 that has been updated since 2013. The latest update being in April 2014. The other versions between 15-24 seem to never have been updated in 2014.

So I am still confused... Is version 12.17 still the mainstream version and considered the Gold standard of Opera browsers until now?

Why didn't Opera prompt us then to install those other versions? like 15, 16,17,18 and 19???? I always thought my browser was up to date...

For some dumb reason, there were no Opera 13 - maybe the guys are "religious" or something. No 14 for Windows either.
The next one was/is the so called Opera 15.
Since this one, the company makes a "new" Opera, based on another engine, etc.

Consider them different browsers. (And you can have both - as I was told.)