I can do this for a single user with:
{
"update": {
"customfield_13200": [
{
"add": {"name": "username"}
}
]
}
}and this works for multiple users if I want to clear the field first:
{
"fields": {
"customfield_13200" : [ { "name":"username1" }, { "name":"username2" }, { "name":"username3" }]
}
}but fails when trying to update (append) with multiple users:
{
"update": {
"customfield_13200": [
{
"add": [ { "name":"username1" }, { "name":"username2" }, { "name":"username3" }]
}
]
}
}