Renamed docID attribute to refID of the <modificationRecord> so the attribute name is consistent; docID attribute is deprecated but remains for compatibility with older documents.

Added <correlatesWith> and <correlation> sub-elements of <uncertainty> element to allow for multiple-dimensioned linear correlation of uncertainty of selected functions and variables.

Added a new element, <contactInfo>, to replace the single <address> element. This format supports multiple ways to indicate the means of contacting the author of a document or reference. <address> is deprecated but is retained for backwards compatibility. This element also replaces the email and xns attributes of <author>.

Fixed a typographical error in <ungriddedTableRef> element: incorrect gtID attributed corrected to utID.

Allowed multiple <author> elements wherever one was allowed before.

Added a new tag, <isStdAIAA/>, to indicate a variableDef refers to one of the standard AIAA variables.

Removed <[un]griddedTable[Ref|Def]> sub-elements of the <confidenceBound> element since this leads to circular logic.

Changed SYSTEM ID to reflect new daveml.nasa.gov domain availability.

Removed e-mail URLs to protect privacy of individual contributors.

Added a new attribute, interpolate, to the <independentVarPts> element to indicate whether the table interpolation should be linear or cubic spline in the given dimension [modified to include quadratic in version 1.9].

Added a new tag, <isState/>, to indicate a variableDef refers to a state variable in the model.

Added a new tag, <isStateDeriv/>, to indicate a <variableDef> refers to a state derivative variable in the model.