Software maintenance stands for all the modifications done after the delivery of a software product. A software maintenance is needed in order to mantain our software up to date.
Modifications in the software may be required because of changes in the market conditions, changes in the client requirements or even host modifications.
There are some types of maintenances based on their characteristics:
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Corrective Maintenance:
This includes modifications and updates done in order to correct or fix problems, which are either discovered by user or concluded by user error reports.
Adaptative Maintenance:
This includes modifications applied to keep the software product up-to date and tuned to the ever changing world of technology and business environment.
Perfective Maintenance:
This includes updates done in order to keep the software usable over long period of time. It includes new features, new user requirements for refining the software and improve its reliability and performance.
Preventive Maintenance:
It aims to attend problems, which are not significant at this moment but may cause serious issues in future.
Sources:
http://swebokwiki.org/Chapter_5:_Software_Maintenance
https://www.tutorialspoint.com/software_engineering/software_maintenance_overview.htm
