The ease of implementation of jQuery in various settings was made possible because of its consistent update. While the early version of jQuery is already impressive, there are situations wherein jQuery might not provide the needed solution. But the update of jQuery is not necessarily a move forward.
There are times that some of the functions were removed or changed which might not work well in various settings. For that reason, some developers ignore the updates from jQuery or forced to use a different framework. Some also use mash-ups so that they can use the same version while providing upgrades in their online application.
The Non-IE Solution (or the Easy Method)
This solution will allow you to load two or more versions of jQuery in one application. In this method, you will simply use two important functions before loading the script from a different version.
You need to set the function to (true) if you want to allow two versions. Of course, using (false) will simply switch the function with a different version off.
The second function is the loading function that will indicate the jQuery version. For example:
If you choose to use Google as the source simply use google.load as the initial function.
The IE Solution (Longer Method)
If you anticipate that your application will be used in IE or if your application will be used by anyone, then you need to use the dynamic loading technique. Basically, this technique can be used if you will be aggressively using a totally different framework.
In this technique, the additional framework merely becomes a node. The only difference is that you can directly point to the source of the library instead of going through append functions just to load a different version of jQuery. A good example is indicating the full URL of the Google API on jQuery so that it can work in the application.