Thanks for confirmation. For some reason , this feature has turned off during the update.
I got one more question regarding extra field, I can not find way to translate "speaker" what name should I look in translation tab?
I can confirm that the extension won't turn it of automatically during the update, so maybe you turned it off by mistake .
Back to your question, the extension doesn't allow you to translate it. So you will need to edit the text in the xml file to change it. Look at the file components/com_eventbooking/fields.xml, you will see the text and can change it