Universität Bremen TZI CBOR (STD 94, RFC 8949) defines the concept of "Deterministically Encoded CBOR" in its Section 4.2, determining one specific way to encode each particular CBOR value. This definition is instantiated by "core requirements", providing some flexibility for application specific decisions; this makes it harder than necessary to offer Deterministic Encoding as a selectable feature of generic CBOR encoders. The present specification documents the Best Current Practice for CBOR _Common Deterministic Encoding_ (CDE), which can be shared by a large set of applications with potentially diverging detailed application requirements. The document also discusses the desire for partial implementations, which can be another reason for constraining CBOR encoders, and singles out the encoding constraint "definite-length-only" as a likely constraint to be used in application protocol and media type definitions. This specification updates RFC 8949 in that it provides clarifications and definitions of additional terms as well as more examples and explanatory text; it does not make technical changes to RFC 8949. // This revision -13 merges all active pull requests in preparation // for the 2025-cbor-17 interim on 2025-10-15.