It is slang that means something like "that is cool" or "I agree with that". Example: "This is the best movie ever!" "Word up!" (I agree)

Check out urban dictionary. https://www.google.com/amp/s/www.urbandictionary.com/define.php%3fterm=word+up&=true

@Gary - I have seen this "Dears" in a lot of emails while working in China, used almost as THE standard greeting in English. @Denis: I would go for Gary's suggestions or "Dear all" in a forum like this, "Dears" definitely sounds wrong in a native environment (OK, except for the grandmother example)

You're welcome. You can use 'Dear friends' or 'Dear colleagues' - which is a little old-fashioned, but OK. But not just 'Dears'. Does the company use that in English? Or in German?

Thx, Gary for comments! I didn't know that "dears" doesn't fit in general:) i work in German company , and all correspondence from their side begins with dears) i thought it was normal [emoji][emoji]