@VictorIvanidze
I think it’s more likely a person will change the reply subject line than go to the bottom of their email, click the dots to expand previous messages, then remove all the previous messages.
Multiple languages is a good point, so I’m using both trigger conditions for my case.
Someone would really have to be trying to get around things if they both removed the RE / FW from the subject line and all the previous message history.
There may be a way around the multiple languages bit though. The message history also includes a From: Name <Email> line. So checking for something like concat(‘<‘, from email, ‘> linebreak-characters’) may work for different languages.
@not(contains(triggerOutputs()?['body/bodyPreview'], concat('<', triggerOutputs()?['body/from'], '>')))
This could also add an interesting difference in functionality where if someone was later added to a thread in a reply message or forward message, then the flow could also trigger the first time they respond in the thread.
So this could be set where the 1st email receives an automatic reply message, then anyone new who responds to the thread also receives the automatic reply message on their 1st response.