A method is disclosed for providing interoperation of a first execution image of a first version and a second execution image of a second version. A compatibility matrix specifies whether the versions are compatible, base-level compatible, or incompatible. In one embodiment, the compatibility matrix may comprise a sparse table that stores a compatibility indicator for all permutations of a plurality of versions of a network operating system. As part of initialization of a system that includes the first execution image and second execution image, version information for the execution images is determined. An entry in the compatibility matrix corresponding to the versions is identified. The execution images are operated in a fully synchronized state when the identified entry of the compatibility matrix specifies that the versions are either compatible or base-level compatible. Individual components of the execution images interoperate according to the results of individual session negotiations. If the versions are incompatible, an alternative redundancy operation mode may be used. Embodiments provide for negotiation of compatible message versions and capabilities among peer components or clients of the execution images as source information to generate the compatibility matrix.