some question about Oem propety

1. according to vendor provide redfish doc, if want to update redfish's ipv6 static ip must send request with

PATCH https://{{ip}}/redfish/v1/Managers/Self/EthernetInterfaces/eth0

{

"DHCPv6": {

"OperatingMode": "Disabled"

},

"IPv6StaticAddresses": [

{

"Address": "5111::100",

"PrefixLength": 64,

"Oem": {

"Ami": {

"StaticIPAddressIndex": 0

}

}

}

]

}

and according to vendor provide redfish doc , updte ipv6 static ip must have below oem property

"Oem": {

"Ami": {

"StaticIPAddressIndex": 0

}

but according to redfish schema
redfish.dmtf.org/schemas/v1/IPAddresses.v1_1_3.json

oem propety should be optional

2. according to vendor provide redfish doc, if want to update firmware, must post request below

POST https://{{ip}}/redfish/v1/UpdateService/upload

Content-Type: multipart/form-data; boundary=-------4939186033593465702222372. 
-------493918603359346570222237

Content-Disposition: form-data; name= UpdateFile ; filename= encrypted_rom.ima_enc

Content-Type: application/octet-stream

<image_binary>

-------493918603359346570222237

Content-Disposition: form-data; name= UpdateParameters ; filename= parameters.json

Content-Type: application/json

{

Targets :[

/redfish/v1/UpdateService/FirmwareInventory/BMC

]

}

-------493918603359346570222237

Content-Disposition: form-data; name= OemParameters ; filename= oem_parameters.json

Content-Type: application/json
{

ImageType : BMC

}

-------493918603359346570222237--

and OemParameters is not optional
but according to www.dmtf.org/sites/default/files/standards/documents/DSP2062_1.0.0.pdf
say "Multipart HTTP push update's OemXXX shoud be optional"

vendor says "according to redfish spec,the required property must exist, and the non-required property is determined by the oem"

is this true "according to redfish spec,the required property must exist, and the non-required property is determined by the oem" ??