You can not link Squeegee to QuickBooks in regards automatic updates and syncing, however you can import the needed information to QuickBooks via a CSV file, downloadable from Squeegee.
In order to get this file go to the reporting tab on squeegee.
One of the first options is labelled Quickbooks Invoices.
Once you have selected this it will ask you for a date range of the invoices you can include, this can be as far back in time as you would like, then select your end date.
Then you will be able to choose what number you wish to choose the invoice to start with, This can be determined by the numbered invoices already in your QuickBooks account.
Then it will ask you for your payments term code for QuickBooks, this will be whatever you have already set up on QB's.
After this you will need to enter the tax code you have set up on QuickBooks.
You will then see the spreadsheet of all of the invoices for the date range you selected, there will be a pink plus button, this when pressed will allow you to download a full CSV file, this file will need to be imported into QuickBooks: