There may come a time when you wish to change/update your logo. After doing so, while it may take up to 15 minutes to fully propagate your account, your browser may also be showing a cached version of the page (with your old logo).
If after 15 minutes you are still seeing your outdated logo on invoices, contracts, etc, simply press the 17hats logo (top left of your page) and allow the page to refresh back to your dashboard overview. This should give you a fresh view of the page but if your browser is still being stubborn and not updating, you will need to manually clear your cookies and cache here.