[jamestenglish]

In my opinion they are the same thing, unfortunately the term SOA has gotten a bit poisoned.

SOA mostly refers to "Enterprise SOA" now and Enterprise SOA has skewed many of the decoupled principles of SOA.

For example Enterprise SOA heavily focuses on middleware, of course all these middlewares are vender specific and create vender lock-in. Microservices mostly focus on just HTTP for their middleware.

Another example of Enterprise SOA is using SOAP and most people configure their SOAP services to have very rigid contracts. So if you update your SOAP service schema to add a field, even if none of your consumers need that field they all need to update their consuming schemas which is very tightly coupled. Microservices should focus on consumer-driven contracts for services.

Language evolves and I would say a lot of people now consider SOA to mean heavy middleware and SOAP with strong contracts creating the new term "microservices" help to differentiate.