10-yr L visa transfer & duration of stay

-I got a new passport (old one expired), can I transfer my 10-yr L visa from my old passport to my new passport, or would I need to re-apply for a new 10-yr L visa for my new passport? I heard it is possible to carry your old passport, which holds the valid 10-yr visa, and new passport together but I am not trying to do that.

-Also, will the duration of stay for L visa holders be automatically extended AGAIN? My initial automatic extension will expire in mid-July. If it won't be automatically extended again, what do I need to do?

Thank you!