The destination address in a telegram can be either a Group Address or an Individual Address.

True. The destination field of a KNX telegram carries a flag bit that tells receivers how to interpret it: when set, the field is a Group Address (multicast to all members of the group); when cleared, the field is an Individual Address (point-to-point, used by ETS for management telegrams). Runtime building automation traffic uses Group Addresses; configuration and diagnostics traffic uses Individual Addresses. Both share the same 16-bit destination field on the wire.

In a group monitor trace, watch the 'destination type' column — Individual Addresses outside of an ETS download window almost always indicate a diagnostic or a misbehaving device.