Hello, jstraub.

I'll share an overview about locking prior periods in QuickBooks. I'll also throw in some extras to help you manage the changes to your old transactions. 

At this time, we can only "close the books" to lock prior period transactions in QuickBooks. 

If ever there are changes to your old transactions, you can view the Audit Log report. It lists all the details when creating or editing a transaction.

Click the Gear icon, then select Audit Log to pull it up. 

Also, you can look for a third-party app that lets you close a specific period without affecting your reports or financials. Simply go to the Apps tab, then search for an app. 

Our developers are working to introduce new features and improve existing ones. They might change the way how you would close or lock your transactions. For now, I suggest checking out our QuickBooks Blog for periodic updates. 

Need help managing your financials such as reconciliation? Check this article for a guide: Reconcile an account in QuickBooks Online. 

I'll give out some guides or important information about QuickBooks' features again. Just let me know if you have other questions about the program. Here to help.