What is synced between Dynamics 365 and Xero?

Invoices

Full details of what is synchronised from Dynamics 365 to Xero are given below.

The following Dynamics 365 Invoice fields are synced from Dynamics 365 to Xero

Branding Theme	Branding Theme
Customer	Contact (see Contacts paragraph)
Date Delivered	Invoice Date
Description	The first 30 character will be set as Reference in Xero.
Due Date	Invoice due date If this is not Xero calculates it based on its rules and it is synced back to Dynamics 365.
Invoice Currency	Invoice Currency
Invoice ID	Invoice number (if Use Xero invoice number is set to No and Use invoice name set to No on the Stellarise Connector Settings page)
Invoice Name	Invoice number (if Use Xero invoice number is set to No and Use invoice name set to Yes on the Stellarise Connector Settings page)
Invoice Type Sales Invoice Purchase Invoice Credit Note	Entity: Sales Invoice Bill Credit Note
Line Amount Types Exclusive Inclusive No Tax	"Amounts Are" Tax Exclusive Tax Inclusive No Tax
Write-In Invoice Product records	Invoice Lines with No ProductCode Description Quantity Unit Price Discount Account Code Tax Rate Tracking option 1 Tracking option 2
Write-In Invoice Product records	Invoice Lines with Not ProductCode Description Quantity = 0 Unit Price = 0 will be created in Xero as "just description" line.
Built-In Invoice Product records	Invoice Lines with ProductCode (see Products paragraph) Description Quantity Unit Price Discount Account Code Tax Rate Tracking option 1 Tracking option 2

Logic:

Invoices are unidirectional, meaning they are transferred one-way: from Dynamics 365 to Xero. Anyway, some information is sync'd back from Xero to Dynamics. See Xero to Dynamics: What is synchronized?

Contacts are only synced if you have Create new contacts in Xero set to Yes in Stellarise Connector Settings.

The following fields are synced from Dynamics 365 Accounts or Contacts to Xero Contacts

Logic:

Customers are unidirectional, meaning they are transferred one-way: from Dynamics 365 Customers to Xero Contacts.
If a Dynamics 365 Customer has not an equivalent Xero Contact, it will then be created in Xero.
If a Dynamics 365 Customer has an equivalent Xero Contact it will then be used as it is.
In Xero, the Contact full name is a Unique Key by itself, meaning no two "John Smith" are allowed to exist. In case of homonyms, the existing Xero Contact will be used! So, pay attention to correctly set Dynamics 365.
If a Dynamics 365 Customer is updated, the changes won't be automatically applied to Xero. You need to manually amend in Xero.
Xero calculates for us various amounts on Contacts. e.g. the Due Amount. These will be sync'd back to Dynamics 365 See 3.5.0 Xero to Dynamics: What is synchronized?

Products are only synced if Create new Products in Xero is set to Yes in your Stellarise Connector Settings.

Following fields are sync'd from Dynamics 365 Invoice Existing Products to Xero Items

Dynamics	Xero
Invoice Product Code	Item Code
Invoice Product Name	Item Name
Invoice Product Price Per Unit	Item Unit Price
Invoice Product Account Code	Item Sales Account Code
Invoice Product Tax Type	Item Sales Tax Rates

Logic:

Products are unidirectional, meaning they are transferred one-way: from Dynamics 365 Products to Xero Items.
If a Dynamics 365 Product has not an equivalent Xero Item it will then be created in Xero.
If a Dynamics 365 Product has an equivalent Xero Item it will then be used as it is.
If a Dynamics 365 Product is updated, the changes won't be automatically applied to Xero. You need to manually amend in Xero.
Write-in products on Dynamics 365 invoices will not be created in Xero as Xero Items, but will be applied on the invoice.