“But microservices want to bring you into tomorrow,” says Winterberg. “Microservices add a bit to the category concept, defining a service over all application layers, including the UI. So people already doing SOA may gain a kind of new freedom by adopting microservice ideas.” That freedom includes technology independence and an alternative to aging technologies, because individual services within an application can be gradually swapped out for those based on more-modern technologies, without having to replace the entire application. “Classic SOA is more platform driven, so microservices offer more choices in all dimensions,” says Winterberg.
The picture that emerges is not of microservices as an alternative to SOA, but rather as a way to restore flexibility that may have been lost in SOAs that became too rigid and monolithic.