Software maintenance
Contract Law

One of the common definitions of maintenance in English law is "... to maintain is to keep something in existence in a state which enables it to serve the purpose for which it exists": Haydon v Kent County Council (1978). The term "software maintenance" is commonly in industry in the following senses:

1. Maintenance is the activity of correcting errors in operational software
2. Rather than distinguishing maintenance activities as the class of activities defined by a reason or motivation to change a program, maintenance may be considered any change that may be made to software that is expected to take less than a specified amount of time.
3. the IEEE (the Institute of Enlectrical & Electronics Engineers) states that the "official" definition of software maintenance is the set of activities involved in making any change to operational software, for any reason. Under this definition, modification of a software product after delivery to correct faults, improve performance, improve some other attribute of the software, or to adapt the product to a modified environment all constitute software maintenance.

This variation of possible meanings of software maintenance is a good example of how the interpretation of terms contained in a contract may vary, and why it is important for contracting parties to define what is actually meant by the use of the contract terms.  In respect to an obligation to provide software maintenance services under the contract, a service provider would probably prefer the definitions (1) and (2) above, whereas the customer would also certainly prefer the defintion appearing at (3) above.