Thanks @avl for the quick reply. I'll stay with the old version until the new one is released, it's not a big problem now that I know the cause.

I'm running Opera 30.0.1835.59 on Ubuntu precise (12.04.5 LTS) (x86_64; GNOME).
It's upgraded itself for months using Opera's repository

deb http://deb.opera.com/opera-stable/ stable non-free #Opera Browser (final releases)

Now it suddenly fails. This is the error message I see if I try to upgrade from command line

$ sudo apt-get install opera-stable
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 opera-stable : Depends: libfontconfig1 (>= 2.9.0) but 2.8.0-3ubuntu9.1 is to be installed
                Depends: libglib2.0-0 (>= 2.37.3) but 2.32.4-0ubuntu1 is to be installed
                Depends: libharfbuzz0b (>= 0.9.11) but it is not installable
                Depends: libnss3 (>= 2:3.15) but 3.17.4-0ubuntu0.12.04.1 is to be installed
                Depends: libpango-1.0-0 (>= 1.14.0) but it is not installable
                Depends: libpangocairo-1.0-0 (>= 1.14.0) but it is not installable
                Recommends: pepperflashplugin-nonfree but it is not installable
E: Unable to correct problems, you have held broken packages.

It seems that there are new dependencies and a mix of older and newer required versions.

Notice that I have installed these versions of those non installable libs (output of dpkg -l)

ii  libpango1.0-0      1.30.0-0ubuntu3.1
ii  libharfbuzz0a      0.9.19-1~precise1~test1

There are no candidates for installing libpangocairo.

I had no problems installing Chrome 43.0.2357.132 and Chromium 37.0.2062.120 (Developer Build 281580) which should use the same engine of Opera.

Did anything change in the build process for the binary distributed through the repository?