2026-05 - SysML v2 Release

Pilot Implementation

NOTE. Language and API implementations are now being distributed under the Eclipse Public License (EPL), rather than the GNU Lesser General Public License (LGPL). See the LICENSE file for details.

This is an incremental installation release of the pilot implementation of the SysML v2 language, API and services. Release notes for the language implementation are available at

• SysML v2 Pilot Implementation - 2026-05

The SysML v2 API and Services implementation is unchanged from the 2025-04 release:

• SysML v2 API and Services - 2026-04 (only license change)

The API Cookbook is unchanged from the 2025-02 release:

• SysML v2 API Cookbook - 2025-02

Standard Library Models

The release includes four versions of the standard model libraries:

• sysml.library – textual notation
• sysml.library.kpar – textual notation packaged in KerML Project Archive (KPAR) files
• sysml.library.xmi – XMI representation, without derived property values or implied relationships
• sysml.library.xmi.implied – XMI representation, without derived property values but with implied relationships

Note. The XMI files (.kermlx and .sysmlx) use an Eclipse XMI representation that is not fully normative OMG XMI.

Textual and Graphical Notation BNF

The release also includes files collecting the BNF specifications for the KerML textual notation and the SysML textual and graphical notation. The BNF in these files was extracted from the specification documents using automated tooling and then manually corrected for editorial errors (which will all ultimately be fixed in the specifications).

The BNF is provided in two formats:

• .kebnf and .kgbnf files – Plain text format for textual notation Extended BNF (EBNF) and graphical notation Graphical BNF (GBNF)
• .html files – Hyperlinked HTML format for textual notation EBNF and graphical notation GBNF

Installation

To install, download and decompress one of the files below and follow the instructions in the README file.

Note. Even though the files below are labeled "Source code", they simply contain the entire compressed contents of this repository. They do not actually include the pilot implementation source code, which is maintained in separate development repositories.

Issue Resolutions

This release includes the Beta 1 versions of the KerML 1.1, SysML 2.1 and Systems Modeling API 1.1 specification documents. These update the formal version of the document with issues approved by Ballots 1 and 2 of the KerML 1.1, SysML 2.1 and Systems Modeling API 1.1 Revision Task Forces (RTFs). Note, however, that these resolutions must be considered preliminary until the FTFs complete and their reports are approved by the OMG.

Resolutions to the following issues are included in this release. The subclauses of each document affected by a resolution are tagged in the document with the corresponding issue key and title. In addition, the doc/changes directory includes PDF cumulative comparison documents between the Beta 1 and published 1.0/2.0 versions of the specification documents.

Note that some of the issues effect the library models and are not reflected in the documents.

KerML Specification

KERML11-2 Occurrence::surroundedByOccurrences::surroundingSpace should not be an end feature
KERML11-4 Error in constraint checkMultiplicityTypeFeaturing
KERML11-6 Error in constraint checkFeatureParameterRedefinition
KERML11-7 Error in constraint deriveFeatureFeaturingType
KERML11-9 Typo in documentation of Transfer::isInstant
KERML11-10 keywords 'standard' and 'library' are missing in list of keywords
KERML11-11 isCompatibleWith operation needs a return type
KERML11-13 Editorial mistake in explanation of composite or portion feature
KERML11-70 FeatureChainExpression semantic constraint OCL is wrong
KERML11-74 Typo in OCL constraint
KERML11-77 The term "connector end multiplicities" not updated to "connector cross multiplicities"
KERML11-81 Abstract syntax XMI contains spurious associations
KERML11-82 Error in constraint checkFeatureFlowFeatureRedefinition
KERML11-83 Missing Metamodel Definition / Misprint
KERML11-85 Redundant paragraph
KERML11-89 Typo in feature myStats : States
KERML11-91 deriveMetadataAccessExpressionReferencdElement misspelled
KERML11-92 Typo
KERML11-93 Suspicious use of the term 'front' instead of "font"
KERML11-94 Wrong reference for Association Structure
KERML11-95 Weak reference for Association Structure
KERML11-107 Description Text in Occurrences Library Crossed
KERML11-108 Grammar rules missing "=" or incorrectly using ":"
KERML11-109 Typos: Relationsip, Relatioship, Instatiated, Namspace
KERML11-110 Feature grammar rule has extra close parenthesis
KERML11-111 Incorrect prefix in "s.isSufficient" and "e.ownedRelationship"
KERML11-112 "C" in "MetaClassificationTestOperator" should be lowercase
KERML11-113 FunctionOperationExpression references missing InvocationTypeMember rule
KERML11-114 Flow and SuccessionFlow reference missing ItemFlowDeclaration
KERML11-115 PayloadFeature grammar rule has mismatched parentheses
KERML11-144 Discrepancy between documentation of Collections library in spec and textual notation file

SysML Specification, Part 1: Language

SYSML21-2 Textual notation vehicle.drives references a vehicle feature that doesn't exist
SYSML21-4 Error in constraint checkConstraintUsageCheckedConstraintSpecialization
SYSML21-6 Remaining error in TradeStudies model
SYSML21-8 Error in usage-node production (occurrence-refxfx)
SYSML21-11 Section 8.2.2.1.2 Lexical Structure
SYSML21-13 Error in constraint deriveSatisfyRequirementUsageSatisfyingFeature
SYSML21-14 There are still references to "FlowConnection" in the specification
SYSML21-15 Error in constraint validateAssignmentActionUsageReferent
SYSML21-17 Error in constraint validateAssignmentActionUsage
SYSML21-20 Mistakes in representative graphical notation of enumeration definition
SYSML21-21 action-def-name-compartment mistake
SYSML21-23 Actions::acceptActions descriptions are different
SYSML21-24 Actions::AcceptAction descriptions differ
SYSML21-25 Actions::DecisionTransitionAction has different descriptions
SYSML21-26 Actions::DecisionAction descriptions are different
SYSML21-27 Actions::MergeAction descriptions are different
SYSML21-29 Actions::AcceptMessageAction has different descriptions
SYSML21-30 Actions::SendAction descriptions not the same
SYSML21-37 source multiplicity wrong
SYSML21-39 validatePortDefinitionNestedUsagesNotComposite is not defined
SYSML21-41 /conjugatedPortDefinition definition missing
SYSML21-44 checkPartUsageStakeholderSpecialization description wrong
SYSML21-46 checkItemUsageSubitemSpecialization has no description
SYSML21-47 ItemUsage is a ItemUsage is wrong
SYSML21-72 Incorrect action name in graphical notation example
SYSML21-140 Package import wildcard is missing
SYSML21-196 Name misplaced on action symbol parameter
SYSML21-209 Differentiate Row Headers that say "Interface"
SYSML21-211 Filter condition or view condition?
SYSML21-232 Incorrect GBNF production relationship-name
SYSML21-240 Library description of Duration of is truncated
SYSML21-262 Documentation compartment name
SYSML21-271 Cosmetic Changes to Table Examples
SYSML21-299 Constraint checkIncludeUseCaseSpecialization is misnamed
SYSML21-301 Viewpoint specialization constraints are incorrect
SYSML21-306 Constraint checkDecisionNodeOutgoingSuccessionSpecialization OCL is wrong
SYSML21-309 Constraint checkRequirementUsageObjectiveRedefinition needs to handle feature chains
SYSML21-314 Textual Notation Potentially Incomplete
SYSML21-317 Verification Case Verdict - Incorrect Verbiage
SYSML21-319 AnnotatingMember does not allow visibility
SYSML21-328 OCL errors in AssignmentActionUsage semantic constraints
SYSML21-330 fs1+fs2 instead of bs1+fs2
SYSML21-331 Grammar, 8.3.21.8_RequirementsDefinition
SYSML21-335 No Equals Sign for PackageMember
SYSML21-339 miss spelling
SYSML21-340 too many the
SYSML21-342 Error in constraint checkSendActionUsageSubactionSpecialization
SYSML21-343 Errors in implied relationships tables
SYSML21-344 Error in constraint validateAssertConstraintUsageReference
SYSML21-348 Connections::BinaryConnection not Connections::BinaryConnections
SYSML21-350 Missing Metamodel Definition / Misprint
SYSML21-362 calc defs '[' for vector and tensor quantity values missing nonunique
SYSML21-363 renderings with an "s"
SYSML21-366 Error in FramedConcernUsage production
SYSML21-370 Typo montonically in Time::Clock
SYSML21-379 crosses instead of crossing
SYSML21-399 Typos: Namspace, Refefinition, Relationsuip, Relationsup, Eleemnt
SYSML21-400 ControlNodePrefix missing closing quote after 'individual
SYSML21-401 TriggerExpression missing closing quote after 'at
SYSML21-402 Product definitions missing = or incorrectly using :
SYSML21-404 PayloadFeatureSpecializationPart grammar uses unknown -> operator
SYSML21-407 Incorrect prefix in s.ownedRelationship
SYSML21-408 SendReceiverPart should be SenderReceiverPart
SYSML21-409 DefinitionExtensionKeyWord should be DefinitionExtensionKeyword
SYSML21-411 Incorrect Page Numbers for pages 1,2
SYSML21-413 Wrong action example
SYSML21-419 Derivation of ownedMetadata is incorrect
SYSML21-420 Typo in Textual Notation about Verification Cases
SYSML21-428 Incorrect allocations compartment
SYSML21-445 Incorrect equals sign in «rep» elements
SYSML21-450 should have no semi-colon (3 places)
SYSML21-455 Incorrect qualified names instead of feature chaining in swimlane examples
SYSML21-456 Typo in clause 7.26.4
SYSML21-457 Typo in GridView description
SYSML21-459 Constraints validateAcceptActionUsageParameters and validateSendActionParameters are incorrect
SYSML21-477 Visibility for import missing
SYSML21-508 Sample Text Notation Error
SYSML21-511 Incorrect bolding in graphical notation example Attributes Compartment
SYSML21-512 checkFlowBinarySpecialization not correct name
SYSML21-513 FlowConnectionFlows::Message Not correct
SYSML21-516 Difference between satisfy line between graphical notation chapter and table in Requirements chapter.
SYSML21-526 SysML.sysml doc wrong
SYSML21-537 Subject node in Use Case example is missing guillemets
SYSML21-540 Duplicated paragraphs in Quantities Calculations overviews

SysML Specification, Part 2: SysML v1 to v2 Transformation

SYSML21-542 Transformation: overview tables shall be revised

Systems Modeling API and Services Specification

SYSMOAS11-15 What Language is are these models in
SYSMOAS11-64 The meaning of root elements isn't clear