= Upgrading From Model-Glue 2 =

Upgrading from Model-Glue 2 to Model-Glue 3 has been designed to be as painless as possible. Great pains went into ensuring backwards compatibility as much as humanly possible.

The process to upgrade from Model-Glue 2 to Model-Glue 3 should be as easy as replacing your existing !ModelGlue directory with a fresh MG3 copy. Sounds easy, doesn't it?

Well, we wish it were. There are a few issues that might trip you up. We'll explain what they are and how to get around them:

1. !ColdFusion 9 introduced the '''trace()''' method. This conflicts with the MG trace method on !EventContext.cfc. You will need to update your codebase and change all instances of '''trace()''' to '''addTraceStatement()'''

2. Model-Glue 3 requires at least version 1.2 of the !ColdSpring Framework (http://www.coldspringframework.org/).

3. The names of the arguments of the '''forward()''' method in !EventContext.cfc have changed. The order of the arguments remain the same, so changing your '''forward()''' calls using from named arguments to ordered arguments resolves this issue.

4. The '''forward()''' method in !EventContext.cfc does ''not'' preserve the state by default in Model-Glue 3. The default in Model-Glue 2 was for '''forward()''' calls to preserve the event state. To have a forward preserve the event state in Model-Glue 3, set the third argument to true. If you are not already passing a second argument, you can set it to "" (the default).