This was originally reported as a Spring Boot issue [1]. CompressionConfig only considers a single Accept-Encoding request header. When the request contains more than one such header, compression may not be used depending on which of the headers in considered. The problem also occurs with 8.5.x. [1] https://github.com/spring-projects/spring-boot/issues/18176
There were other issues with the parsing such as xxgzip being treated as meaning gzip was supported. Those have been fixed as well. Fixed in: - master for 9.0.25 onwards - 8.5.x for 8.5.46 onwards - 7.0.x for 7.0.97 onwards