2021-01-31: Added missing AdapterConnections? sub-element of SubAppNetwork element in LibraryElement.dtd.

2020-07-29: DataType.dtd and LibraryElement.dtd have been updated to accommodate the proposed use of packages for Library Management.

2020-05-15: LibraryElement.dtd has been updated to accommodate the proposed use of Simple EC States, ECCs, and FB Types.

2019-12-30: Removed <?xml version="1.0" encoding="UTF-8"?> headers from DTDs. This header is not required by the DTD syntax and is interpreted as an error by some XML parsers.

2019-05-22: DUPLICATE_OBJECT, INVALID_DST, NULL_POINTER, INTERRUPTED, and UNKNOWN have been added to the list of Response.Reason attribute values in FBMGT.dtd.

2018-01-24: To accommodate the proposed use of Transient EC States, LibraryElement.dtd has been modified to allow ECCs containing zero or more EC Transitions. Basic FB Types developed with earlier versions of this DTD are forward-compatible with this DTD.

2017-11-15: A question mark "?" has been added to the end of the list of contents options in the definition of Request in FBMGT.dtd in order to avoid a conflict with the semantics of the START and STOP actions as defined in Table 6.5-1 of the Compliance Profile.

2011-08-22: LibraryElement.dtd has been updated as follows, in anticipation of corresponding changes in IEC 61499-2, 2nd Edition:.

• Missing x,y parameters have been added to AdapterDeclaration.
• Algorithms now have the possibility to have VarDeclarations of temporary variables.
• Applications now contain SubAppNetworks instead of FBNetworks.
• It is now possible to declare (network) SegmentTypes.
• An optional CompilerInfo sub-element has been added to the System element.
• CDATA sections may now be used to represent the text of algorithms in ST and Other languages, and the Expression portion of LD Rung elements.

2010-09-28: A Parameter element has been added to FBMGT.dtd for use in READ/WRITE operations, in anticipation of the corresponding change in the 2nd Edition of IEC 61499-1.

2010-08-07: FBMGT.dtd has been updated as follows:

• RESET has been added to the list of enumerated values for the Request.Action attribute. This action is present in Figure 24 of IEC 61499-1, but was missing in Table 8 (this will be corrected in the next Edition of 61499-1).
• The list of enumerated values of the FBStatus.Status attribute has been changed from (INITIALIZED|WAITING|EVALUATING|PROCESSING|STOPPED|KILLED) to (IDLE|RUNNING|STOPPED|KILLED) for consistency with Figure 24 of IEC 61499-1 The previous list was from a very early Industry Technical Agreement (ITA) and was rarely if ever implemented.

2009-03-07: LibraryElement.dtd has been updated to correct an error in the definition of the Application element. XML files of IEC 61499 system configurations produced by previous versions of the FBDK prior to this update may not comply with these DTDs. The XMLChecker application can be used to check for this compliance.