I installed a plugin to make translations of my theme and received the following warning concerning Contact Form 7 (version 2.4.4):
Loading Issue: Author is using load_textdomain instead of load_plugin_textdomain function. This may break behavior of WordPress, because some filters and actions won't be executed anymore. Please contact the Author about that.
Please note that I didn't try to translate Contact Form 7 itself (seems to be already done by others). This is the warning I received in the admin area list.