...

Both of the above increase the amount of data which needs to be downloaded from the server to the browser. However, concatenation still does have its place due to compression ratios. Generally, larger files yield better compression results, thus reducing the total overall file size of your page.

HTTP 2.0 support

Tomcat 8.5 upgrade to HTTP 2.0: http://tomcat.apache.org/tomcat-8.5-doc/config/http.html#HTTP/1.1_and_HTTP/1.0_Support

Tomcat 8.5 Connector configuration: http://tomcat.apache.org/tomcat-8.5-doc/config/http.html

JBoss EAP 7.0: https://access.redhat.com/documentation/en-US/Red_Hat_JBoss_Enterprise_Application_Platform/7.0/pdf/Configuration_Guide/Red_Hat_JBoss_Enterprise_Application_Platform-7.0-Configuration_Guide-en-US.pdf

Websphere: it seems that Websphere currenlty does not support HTTP 2.0 (https://github.com/http2/http2-spec/wiki/Implementations)

Further reading: https://deliciousbrains.com/performance-best-practices-http2/