Sometimes you may look at the invoice statistics (located on the work order screen or in the invoices sections)
And find that the calculations do not seem correct. These are calculated based on the fiscal year setting in the settings screen - tenant tab. So if your year end is set to December then the invoice statistics will show all invoice calculations from Jan 1 to Dec 31 of that year.
So if you run into the problem where the invoice statistics do not look the way you expect. Please check Settings -> Tenant -> Fiscal Year End Dropdown to change the month to the Year end month for your company.