According to http://maven.apache.org/guides/mini/guide-http-settings.html#The_Basics PUT requests made with the HTTP wagon will enable Expect-Continue support by default.
However testing shows that when no <httpConfiguration> is provided in settings.xml Expect-Continue support is not enabled by wagon-http for PUT requests.
Similarly, when an empty <httpConfiguration> section is provided in settings.xml, Expect-Continue support is not enabled by wagon-http for PUT requests.
Only when a <httpConfiguration> section like:
is provided in settings.xml is Expect-Continue support enabled.