Apple Watch Battery Replacement in store or mail in?

[mk313]

Either I'm the world's worst searcher or I'm misremembering this. I feel like I saw a thread or several threads about the Apple Watch needing to be sent in for service (that it can't be serviced in store). My searches give me hundreds of results but nothing that I can see that is helpful or even related to Apple Watch battery replacement.
My battery is getting close to 80% and now that I've seen the specs on the 7, I"m going to hold on to my 5 for another year. When you have service done, can they do it in store or do they need to mail it out?
Thanks in advance,

 

[ericg301]

you need to mail it out because they don't replace the battery, they replace the whole unit.

someone earlier in the week posted that they sent out their S5 and got an S6 back. so you never know.

 

[mk313]

you need to mail it out because they don't replace the battery, they replace the whole unit.

someone earlier in the week posted that they sent out their S5 and got an S6 back. so you never know.

Thank you!