There are really only two main changes which are likely to affect existing users, and all other changes required in user's applications mostly flow from these two changes:
All Swarm functionality is now exported through a single, well-defined interface: Objective C protocols. Essentially this means that all creatable or subclass-able protocols now follow the same conventions as those in the defobj, activity and collections libraries. This means that static typing of Swarm protocols is now obsolete across the whole package.
Library header files no longer include any of their individual class header files.
The XPixmap protocol has now
            been changed to Pixmap to divorce
            itself from it's association with
            X-Windows.
Any subclass of a class defined as a Swarm
          protocol now requires the *specific* importation of that
          protocol's header file.  Previously, only a warning was
          raised.  This particularly affects
          Swarm and
          SwarmObject.  If you define something
          like:
@interface MyObject: SwarmObject
then you need to include:
#import objectbase/SwarmObject.h
 
          Similarly, if you subclass from Swarm, you will require
            objectbase/Swarm.h 
All references to objects conforming to Swarm protocols should either be defined to conform to the appropriate Swarm protocol, or be left untyped. In no circumstance should it be statically typed. In practice, this means that you can write, either:
id Grid2d world; OR id world;
but NOT
Grid2d *world;
Note that this only applies to protocols defined by Swarm proper, not to your own classes, although it is good practice to adopt a convention and stick to it.
HeatSpace.h
Include header file for
          space/Diffuse2d (x)
Heatbug.h
Make instance variable world conform to protocol:
              id Grid2d world NOT
              id Grid2d *; (x)
Heatbug.m
In [Heatbug -setWorld:] method:
          make cast to protocol not static (x)
HeatbugModelSwarm.h
HeatbugObserverSwarm.h
Make instance variable id Grid2d
                  world NOT Grid2d *world (x)
Change static cast of [HeatbugObserverSwarm
                  -getWorld:] method to protocol version (x)
Change all the below to conform to their respective protocols (x)
                  EZGraph *unhappyGraph;
                  Value2dDisplay *heatDisplay;
                  Object2dDisplay *heatbugDisplay;
                
MousetrapModelSwarm.h
Import objectbase/Swarm.h
          for subclassing from Swarm (*)
Remove imports of activity.h
            collections.h simtools.h
            objectbase.h irrelevant, as not used in
            the interface. (x)
Make instance of Grid2d conform to
          protocol, not static typed. (x)
MousetrapObserverSwarm.h
Make instances of EZGraph,
            Object2dDisplay conform to protocol, rather than
            be statically typed. (x)
          
Mousetrap.h
Remove import of
          objectbase.h (x)