Hello @ivynobita ,
standard BGP communities can be used in addition to the extended communities but not in substitution of them.
The Cisco IOS command to use both type of communities is
neighbor x.x.x.x send-community both
in the appropriate address-family.
Some key values like route targets are still extended communities however adding standard communities to the scenario gives some additional capabilties like those to increase local preference for routes including VPNv4 routes or other types of MP NLRIs having a specific standard community attribute to create a primary /secondary routing strategy to multihomed VRF sites or other types of services.
Hope to help
Giuseppe
