As this post from Nexus shows, very soon MO will no longer be able to download from their site unless a change is made to the code MO uses.
As there is, at the moment, no one actively developing for MO 1.3.11 anymore this means in all likelihood it will be rendered obsolete by this change and you will no longer be able to maintain your mod list with automatic downloads as you once could.
Of course the core functionality of MO will remain the same and the modded game will still work, you will just no longer be able to download from within the MO UI.
Fortunately MO2 is very much in full development and this change will be made to its code very shortly. MO2 is a very robust alternative to MO 1.3.11 and if you have been holding off changing over to it may I suggest that you do so immediately.
Full support fot MO2 will be maintained but due to this recent development by Nexus MO 1.3.11 will be slowly phased out and we will be limiting our level of support for it.