Here's some info on these so-called "emergency" updates... at least so far as they may pertain those still using avast 8:
The last version of avast 8 that I knowingly installed on my Win7 system was 8.0.1497, which was released on or about 2013-09-02. It is the last fully-documented version of avast 8 released.
For quite a while, I had a RUN (as opposed to a run-ONCE) startup entry that repeatedly ran a 2013-11-21 emergency update every time I rebooted my system. The RUN was never removed. And that's what started this thread months ago.
Two months later, I eventually decided there was no point running it "forever", and so I manually stopped its auto-booting.
Finally today [2014-02-21], I received a new RUN-ONCE startup entry for a 2013-12-24 emergency update, which ran on the subsequent reboot. The reboot took an exceptionally long time... perhaps while it was downloading/installing/updating the necessary files.
There was no formal indication of what was happening... but suffice it to say I now have a "newer" build of v8 --- 8.0.1504 --- on my system. All I can determine about these newer builds is that each constitutes a "Support version for migration to AVAST 2014". Doing a web search, I learned that apparently there have been several:
avast 8.0.1500 on 2013-10-15
avast 8.0.1501 on 2013-11-01
avast 8.0.1504 on 2013-12-19 (which I believe I only received today)
avast 8.0.1506 on 2014-01-27 (perhaps an indication of something yet to come?)
Note: I am just reporting the facts of my experience. Unless forced, I will upgrade to avast 2014 if and when I feel ready. I know many people will say I should have long ago... but that's my decision... at least for the moment. [In fact, the one time I tried, the installation refused to complete itself.]
For what it's worth, I do run avast 2014 on my Win XP system.
P.S. I have intentionally set "Program Updates" to MANUAL... which is supposed to tell avast neither to check for program updates nor to automatically install them. I find it ironic that so called "emergency updates" --- in this case, merely a "migratory preparation" --- can defy this setting.