In a distributed data processing and deduplication system comprising a plurality of clients and servers, a traditional client library on each client is replaced by a small kernel library and a separate client library which may be either on the client or on a separate server. The kernel library receives an initialization API call from an application on the client, determines the appropriate version of the client library for that application, and directs the initialization call to that client library. The client library returns to the kernel library a list of function pointers to code that implements functions called by the application, and dynamically redirects function API calls from the application to the code. By storing the client library at one central location and updating that one version for changes to hardware and software, multiple client systems may be updated automatically upon initialization to use the new version of the client library.