Save relationships between content types using REST API

[mvelasco]

Question

I have two content types and a relationship 1: N

Content types:  Promotion (parent), Version (child)

Relationship Promotion-Version

I didn't have any problem saving "Versions" but every time I save a Promotion I lost all previous relationships with Versions. 

As documentation says https://dotcms.com/docs/latest/save-content-using-the-rest-api "When updating content using the REST API, you must submit all relationships for a piece of content each time you update the content."

I tried with:

1. {
1. Promotion-Version:"+identifier:(11f3a625-ec65-4414-9c97-84e8e6dc8ede && 35f3ed74-06f2-4463-a4e9-a37823008c9a)"
2. acquisitionoffer:"True"
3. domain:"domain-1"
4. id:"Test 1.3"
5. identifier:"76df92aa-a443-41bd-9818-8afddbe860c6"
6. stInode:"c9cebf62-a542-4197-8f7d-55e004ab8393"
7. type:"Casino"

 }

11f3a625-ec65-4414-9c97-84e8e6dc8ede and 35f3ed74-06f2-4463-a4e9-a37823008c9a are two version of promotion 76df92aa-a443-41bd-9818-8afddbe860c6 But this didn't work.