Can we start next year AP and AR before GL is closed for previous year?

Yes. Make sure to run AP Year-end and AR Year-end.

There is a Period End Checklist available on our Technical Tips page.

I stumbled across this post while searching for something else.
Why do you say to "make sure" to run year-ends in AP & AR? I've never run a year-end in my subledgers and everything is running along just fine. And I frequently post to the next fiscal year in my subledgers before I close the GL year. Just wondering.

Year-ends in AP and AR are optional. But if you want to reset the batch numbers to 1 and move the YTD statistics to Last Year, then you have to "make sure" to run year-end at the proper time.

Steve