Here on the avast forums, most of us don't worry about version numbering as Alwil seems to take a different attitude on avast version numbering, with many of the additions to avast being at most a .1 increment where many other would call that a whole 1 point version increase.
Some of the changes in 4.8 from 4.7 were massive, but still only a .1 increment and we have had program update in 4.8 were only the build number is increased and they would in some other AVs be considered a .1 version increment.
So basically what I'm saying is I don't care what number they call it so long as avast's program development is active and ongoing. Whilst there is a push towards a major build, version 5, they haven't stopped improving the existing version.
When they have some things they are working on which they feel should be included now, that may well be included rather than wait for version 5 (assuming with the existing infrastructure it can be included).
This is why for me numbers are that, just numbers, if we get 4.9 before version 5, I'm not worried, I will accept it happily as I will version 5 when it is eventually released.