Existing 16-bit applications written for OS/2 Version 1.3 may execute under OS/2 Version 2.0 without modification. However, significant enhancements to performance and functionality are possible by taking advantage of additional features provided by the 32-bit OS/2 Version 2.0 environment. In order to take full advantage of the 32-bit environment, applications must be modified to use the new features.
In addition, a number of changes have been made in the 32-bit programming environment to provide improved consistency and ease of use, simplifying the task of learning the operating system interfaces and reducing the amount of coding required by application developers. The incorporation of these changes into applications will also require source code modification.
It is not necessary for applications to migrate all their modules and resources to the 32-bit environment, since OS/2 Version 2.0 allows mixing of 16-bit and 32-bit code and resources within the same application. However, 32-bit modules that make calls to 16-bit modules or resources must be aware of the differences in addressing schemes between the the 16-bit and 32-bit environments.