As a passionate fan of Mew, this comes as a pretty big surprise. I suppose his name, isn't as well known as Jonas Bjerre, and for that matter the Mew name, but the fact is he had been with them for more or less their entire history and was largely responsible for many of the elements to their sound I love. So to say his departure is significant in their future seems likely.
Now, the way that reads below, it says "for the time being" so it may not be permanent. I dunno, it might become like a studio vs live thing, or it may be he needs a break and down the road he may come back.
Mads Wegener I've never heard of, but just using Google, it shows he's a guitar teacher I guess and maybe has played with some bands/projects. One being the Danish band The Storm, which newly returned Mew bassist Johan Wohlert has been involved with when he became a father and had left Mew in 2006. Which The Storm is a band with his wife Pernille Rosendahl.
I guess we'll see what Mads Wegener's role will be and the future of Mew's guitarist. Perhaps even some stuff will be known when they come to the States in the Fall. But it is too bad Bo could not have at least stayed on for that tour.
http://www.mewx.info/bo-madsen-leaves-mew/
Bad news, guys. There had been rumours lately, but now we have a statement from Mew:
“After 20 years playing together in Mew, the band and Bo Madsen have decided to part ways for the time being. At present the rest of us will continue with Mew. We are happy to tell you that guitarist Mads Wegner will be joining us on our upcoming shows, and we look forward to seeing you all out there.
Thank you for your understanding and support.
–Jonas, Johan and Silas.”