Resolution:
Here is a list of Syntax 4 features that EDI 5.2 supports:

Envelope segments

"XEngine/SpecBuilder provide both versions of envelope segments - Syntax
3 and Syntax 4. It's up to user to select desired version of envelope
segments. And XEngine and SpecBuilder can validate them.  

Character Repertoires

XEngine/SpecBuilder support all repertoires except following :

- ISO 10646-1 octet with code extension technique to support UTF-8 (UCS
Transformation Format, 8 bit) encoding

- Code extension technique as defined by ISO 2022 utilizing the escape
techniques in accordance with ISO 2375.

BC supports only ASCII character set. So Chinese characters or other asian characaters are not yet supported. With regards to UNOX\UNOY character sets, we are not claiming conformance on these character sets and this is allowed as per EDIFACT rules. Here is a sample of their rules:

"UNOX\UNOY char sets are to be used only with Syntax 4.  Regarding conformance to the standard EDIFACT states following : Conformance to a standard means that all of its requirements, including all options, are supported. If all options are not supported, any claim of conformance shall include a statement which identifies those options to which conformance is claimed. Data that is interchanged is in conformance if the structure and representation of the data conforms to the syntax rules specified in this International Standard. Devices supporting this International Standard are in conformance when they are capable of creating and/or interpreting the data structured and represented in conformance with the standard."

We can claim conformance to the standard with some exclusions.

Dependency Notes

XEngine/SpecBuilderprovide complete support of these Notes including validation.  BC supports this.

Repeating data elements

Such data elements are supported in XEngine/SpecBuilder.  BC supports this.

UGH/UGT

These segments are supported in XEngine/SpecBuilder. BC supports this.

Interactive EDI

We provide Interactive EDI messages and support their validation in
XEngine/SpecBuilder.

BC does not support I-EDI since the syntax structure is different than as far as Interchange,Group and Message level. We would claim exclusion on Interactive-EDI.

CONTRL

XEngine 6.2 (bundled with EDI 5.2.0) can generate only Syntax 3 version of CONTRL message.

But we can perform validation of both versions as for the rest of EDIFACT messages.

EDI 5.2 does not support creation of Syntax 4 CONTRL, we are claiming exclusion until we release a future version with a later release of the XEngine.

Part 5

We can validate Security segments as any other regular segments if they are provided within message structure, but we will not do anything special with them in XEngine/SpecBuilder.  BC supports this.

Parts 6 - 9

These messages are supported as regular EDIFACT messages in XEngine/SpecBuilder. BC supports this.

BC EDI Support for EDIFACT Syntax 4