IsReleased had a single purpose - due to technical limitations, it was necessary to maintain it in order to get the state of a document as quickly as possible.
But now it's 2022 and the IsReleased attribute has already played its part in ERP.net.
It still exists for backwards compatibility, but we are now officially marking it as obsolete.
What does this mean?
At this point - nothing. It's still available, part of the Domain API, but there are two important details:
1. Because of its depreciation, there's no guarantee that it will be available in future ERP.net releases.
2. In general, we won't address issues, related to this attribute.
Does this change affect me?
Yes, if you use this attribute.
What to do if this change affects me?
Just switch to the document's State attribute.
This means that if you're currently doing this:
GET ~/Crm_Sales_SalesOrders?$filter=IsReleased eq true
Instead, you should do this:
GET ~/Crm_Sales_SalesOrders?$filter=State ge 'Released'