Add info about required KeePassXC version

Author: purejava

README.md

@@ -7,7 +7,7 @@
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-A Java library to access KeePassXC via its build-in proxy.
+A Java library to access KeePassXC via its build-in proxy. Requires KeePassXC 2.6.0 or newer.
 
 # Dependency
 Add `keepassxc-proxy-access` as a dependency to your project.