Changelog

For newer versions, see GitHub Releases

2.90

Release date: 2021-02-24

Fix: use EnvVars.get() instead of TreeMap.get() to guard against stray null value environment variables (JENKINS-64729)

2.89

Release date: 2021-02-17

Fix: Help link positioning for Snippet Generator with tables-to-divs (PR #411

2.88

Release date: 2021-02-15

Fix: Lightweight checkout ignored pipeline durability settings (JENKINS-63305)
Internal: Update various dependencies (PR #404, PR #405, PR #412, PR #413)

2.87

Release date: 2020-11-30

Improvement: Do not check empty value environment variables for Groovy string interpolation. (JENKINS-64282)

2.86

Release date: 2020-11-18

Fix: Revert changes to usage of NamedArgsAndClosure class in version 2.85 that caused various regressions for Declarative Pipelines. (JENKINS-64185)

2.85

Release date: 2020-11-09

Improvement: Add warnings when secrets are used with Groovy String interpolation. (JENKINS-63254)
- Warnings are configured by setting org.jenkinsci.plugins.workflow.cps.DSL.UNSAFE_GROOVY_INTERPOLATION to the following values:
  - ignore: warnings are disabled
  - fail: warnings will cause Pipeline builds to fail
  - not setting any value will display warnings to the console log and build page
Fix: Allow masking of secret variables that use the same name as system variables. (JENKINS-47101)
Fix: Throw an error when a step that requires a body has no body. (PR #370)

2.84

Release date: 2020-10-30

Improvement: Make the Pipeline editor resizable (JENKINS-31592, JENKINS-32297, JENKINS-38276, PR #391)
Fix: Do not save Pipeline state to program.dat when Pipeline resumption is disabled (PR #377)
Internal: Update jQuery by migrating frontend toolchain from js-builder to Webpack (PR #391)
Internal: Update parent POM and various dependencies (PR #380, PR #384, PR #385, PR #387, PR #388, PR #389, PR #390)
Internal: Update some tests to use JenkinsSessionRule (PR #381)
Internal: Add regression tests for SECURITY-2020 (PR #379)
Internal: Enable Dependabot on repository (PR #382)

2.83

Release date: 2020-09-03

Fix: Prevent Pipeline builds from resuming after being aborted while starting (fix also requires Pipeline: Job plugin version 2.40 or newer) (JENKINS-46961)
Improvement: Make logging related to persisting PERFORMANCE_OPTIMIZED Pipelines during Jenkins shutdown more consistent to help diagnose (JENKINS-55287)
Internal: Fix tests causing PCT failures when running against Jenkins 2.236+ (PR 375)

2.82

Release date: 2020-07-30

Fix: In some cases, block-scoped steps that had already completed could be persisted in serialized Pipelines, causing the already-completed steps to resume when the Pipeline resumed. (JENKINS-63164)

2.81

Release date: 2020-06-30

Fix: Iterators for types such as LinkedList that implement Deque in addition to List no longer cause intermittent serialization errors. Iterators for types that only implement Deque are now serializable as well. (JENKINS-62659)
Improvement: When using failFast: true with the parallel step and one of the parallel branches fail, the exception thrown in the other branches now includes the name of the branch that failed originally. (PR 353)
Improvement: Use four spaces for indentation in sample Pipelines instead of three. (PR 349)
Developer: Make Snippetizer.object2Groovy and SnippetizerTester.assertGenerateSnippet accessible from other plugins, and add new SnippetizerTester.assertParseStep method for testing backwards compatiblity of step data binding. (PR 362, PR 364)
Internal: Update parent POM, dependencies, and minimum core version to 2.176.4. (PR 355)

2.80

Release date: 2020-02-14

Fix: Always link the bindings of scripts loaded via the load step back to the binding for the main Pipeline script when a Pipeline is resumed. Previously, the bindings in the loaded script could become out of date in some cases. (PR 348)
Developer: Introduced GroovySample extension point to allow plugins to dynamically add samples to (or filter samples from) the dropdown menu shown when configuring a Pipeline script in Jenkins. (PR 350)

2.79

Release date: 2020-02-12

Security: Fix sandbox bypass vulnerability. (SECURITY-1710)

2.78

Release date: 2019-12-10

Fix: Resume Pipeline execution if Jenkins shutdown is canceled. Previously, when Pipelines were paused because Jenkins was preparing for shutdown, they remained paused even if shutdown was canceled. (JENKINS-34256)

2.77

Release date: 2019-11-26

Fix: Make the parallel step propagate the worst result of all branches when not using failFast: true. Previously, the propagated result was the result of the first branch that completed. Note that before Pipeline: Build Step Plugin version 2.10, which changed the way that results are propagated for the build step, it was rare for there to be a distinction between the old and new behavior in practice. (JENKINS-49073)
Improvement: Improve diagnostics and robustness for Pipeline-specific Whitelists. (PR 338)
Internal: Update workflow-step-api to no longer rely on a beta API. (PR 327)

2.76

Release date: 2019-11-12

Fix: Prevent block-scope steps implemented using GeneralizedNonBlockingStepExecution (such as withCredentials and wrap) from hanging indefinitely in some scenarios. (JENKINS-58878)

2.75

Release date: 2019-10-31

Fix: Do not log CPS method mismatch warnings for invocations of closures stored in class fields or maps. (JENKINS-58407)
Fix: Do not log CPS method mismatch warnings when the receiver is defined in a Jenkins Plugin. (JENKINS-58643)
Fix: Do not log CPS method mismatch warnings for uses of GroovyShell.evaluate. (JENKINS-58620)
Improvement: Make the error that is thrown when the script for a Pipeline definition cannot be found in the configured SCM clearer. (JENKINS-59425)
Improvement: Add Declarative Pipeline samples to the editor for Pipeline jobs. (JENKINS-42471)
Internal: Refactor code to use Java 7+ language features, improve performance, clarity, and coverage of tests, and migrate Wiki content to GitHub (PR 310, PR 321, PR 322, PR 330, PR 331, PR 333)

2.74

Release date: 2019-08-24

Fix: Do not attempt to store enums defined in Pipeline scripts that are passed as arguments to Pipeline steps in ArgumentsActionImpl to avoid leaking Pipeline script class loaders. (PR 318)
Fix: Do not try to open the listener for a completed build when looking up environment variables through EnvActionImpl. (JENKINS-59083)
Internal: Add regression tests for SECURITY-1465. (PR 310)

2.73

Release date: 2019-08-01

Fix: The generated GDSL file used to support syntax highlighting for Pipeline scripts in IntelliJ IDEA incorrectly reported some step parameter types as Map when they should have been List, and did not support the parallel step. (JENKINS-30572)
Fix: Do not log CPS method mismatch warnings for some false positives related to metaprogramming. (JENKINS-58501)
Improvement: Log a warning when named arguments passed to a Pipeline step cannot be bound to any parameter of that step (for example because the argument is spelled incorrectly). Previously, such arguments were silently ignored. (JENKINS-33217)
Improvement: Integrate the StepListener API added to Pipeline API Plugin version 2.36 (JENKINS-58084)
Internal: Add additional tests for false positive CPS mismatch warnings (PR 309)
Internal: Speed up some tests using ClassRule. (PR 308)
Internal: Migrate tests related to snippet generation for the build step to Pipeline Build Step Plugin (PR 303)

2.72

Release date: 2019-07-11

Fix: Prevent a StackOverflowError from being thrown when calling overridden methods using super in some class hierarchies in a Pipeline. (JENKINS-52395)
Internal: Update tests to fix PCT failures and unignore tests that no longer fail. (PR 290, PR 302)

2.71

Release date: 2019-07-05

Fix: Allow script-level initializers (including @Field) in sandboxed Pipelines. Fixes a regression from version 2.64. (JENKINS-56682)
Improvement: Print detailed warnings to the build log when CPS-transformed code is called in a non-CPS context where possible. The warnings link to https://jenkins.io/redirect/pipeline-cps-method-mismatches/ which gives additional context and some examples of how to fix common issues. (JENKINS-31314)
Fix: Catch additional types of exceptions when calling GraphListener methods. (PR 292)
Internal: Build and test on Java 11, light refactoring and simplification, fix flaky test. (PR 294, PR 295, PR 296, PR 298)

2.70

Release date: 2019-06-03

Improvement: Interpret the DynamicContext extension point added in Pipeline Step API Plugin version 2.20. (JENKINS-41854)

2.69

Release date: 2019-05-28

Fix: Prevent a memory leak that could occur when shared libraries were used inside of a node step. (JENKINS-50223)
Fix: Make an internal collection thread-safe to prevent an IOException with the message "cannot find current thread" from being thrown intermittently when using some types of non-blocking steps. (JENKINS-56890)

2.68

Release date: 2019-05-10

Fix: Improve handling of step arguments that cannot be data-bound. Fixes some cases where a non-fatal NoStaplerConstructorException would be visible in logs. (JENKINS-54186)
Fix: Simplify stack traces for code inside of Pipeline libraries to avoid issues deserializing those stack traces. (JENKINS-57085)
Fix: Make the support bundle component that provides Pipeline timing information more robust so that errors in one build do not keep timing information from being added to the support bundle for other builds. (PR 283)

2.67

Release date: 2019-04-19

Improvement: Better handling of RejectedAccessException within try/catch and catchError blocks. (JENKINS-34973)

2.66

Release date: 2019-04-11

Fix: parallel and load steps did not clean up internal state correctly after their executions completed, leading to failures upon resuming a Pipeline and various kinds of memory leaks in some cases. (JENKINS-41791)
Fix: When checking out a Pipeline from SCM, the support for SCM retry count did not retry the checkout attempt for certain kinds of errors when it should have. (PR 274)
Improvement: Avoid logging certain kinds of unhelpful warnings when determining whether a Pipeline should block Jenkins from restarting (PR 277).
Improvement: Update samples to use the non-deprecated archiveArtifacts step instead of archive. (PR 273)
Improvement: Fix documentation for the params variable explaining how to use it with a default value. (JENKINS-56688)
Improvement: Add internationalization support and Chinese localization for "Pipeline Syntax" links. (PR 276)

2.65

Release date: 2019-03-25

Fix security issue

2.64

Release date: 2019-03-06

Fix security issue

2.63

Release date: 2019-02-01

Enhancement: Enable the StepEnvironmentContributor extension point added in version 2.19 of Pipeline Step API Plugin (JENKINS-51170)
Fix: Notify global GraphListener implementations of FlowStartNodes when a Pipeline build begins (JENKINS-52189)

2.62

Release date: 2019-01-14

Fix: Trim Pipeline script path (e.g. Jenkinsfile) when using a Pipeline script from SCM (JENKINS-55424)
Add a link to Pipeline Examples from the sidebar of the Pipeline Syntax page.
Add support for GeneralNonBlockingStepExecution utility added to Pipeline Supporting APIs 2.18 (JENKINS-49337)
Avoid use of deprecated APIs (PR 256)

2.61.1

Release date: 2019-01-08

Fix security vulnerability

2.61

Release date: 2018-11-30

Fix: Catch errors thrown by GraphListeners during Pipeline execution so that they do not cause the build to fail (JENKINS-54890)
Improvement: Only construct log messages when the specified logging level is enabled to improve performance in some cases

2.60

Release date: 2018-10-29

Fix security issue

2.59

Release date: 2018-10-17

Improvement: Limit the types of Step arguments stored for visualization (JENKINS-54032)
- Solves memory leaks for some plugins that abuse Step arguments by passing Pipeline-internal objects
- Better protects against storing potentially problematic object types, and may reduce their memory use
- Applies filtering to Describable objects passed by legacy syntaxes, so that filtering can be applied to their fields

2.58

Release date: 2018-10-12

Internal bug fix important for display of steps in classic UI after update of Pipeline Job Plugin to 2.26.
Minimum Jenkins Core version updated to 1.121.1

2.58-beta-1

Release date: 2018-10-04

Internal bug fix important for display of steps in classic UI after update of Pipeline Job Plugin to 2.26-beta-1.

2.57

Release date: 2018-10-02

Fix: Make compilation errors when using the load step serializable so that the actual compilation error is reported instead of a NotSerializableException (JENKINS-40109).
Improvement: Add localization support for a message on the global variable reference page.

2.56

Release date: 2018-09-27

Fix: Do not persist Pipeline context variables that are no longer in scope. In particular, this fixes some cases where resuming builds outside of a node block would wait for an agent used previously in the Pipeline to become available (JENKINS-53709)
Improvement: Chinese localizations have been migrated to the Localization: Chinese (Simplified) Plugin.

2.55

Release date: 2018-09-19

Improvement: Allow steps to be invoked using their full class name to avoid ambiguity, and log a warning when ambiguous steps are invoked (JENKINS-53333)
Various documentation and localization improvements.

2.54

Release date: 2018-06-25

Fix: Do not use com.google.common.io.NullOutputStream

2.53

Release date: 2018-05-08

Fix: Fix deadlocks with WorkflowRun#copyLogs() + CPS things (tracked in comments for JENKINS-51132)

2.52

Release date: 2018-05-04

Fix: Fix a critical deadlock with CpsFlowExecution#getCurrentHeads introduced in 2.50 due to jenkinsci#223 (JENKINS-51132)

2.51

Release date: 2018-05-03

Fix: Allow the FlowExecution to still be saved if a Pipeline build (WorkflowJob) is modified and saved before the lazy load of the FlowExecution is done (onLoad not invoked on the execution) (JENKINS-50888)

2.50

Release date: 2018-05-02

We strongly encourage installing this update due to the issues resolved, and suggest combining with an upgrade to Pipeline Job (workflow-job) plugin v2.21 or later
Major Fix: NullPointerException in CPS VM thread for builds with certain data not properly persisted (JENKINS-49686)
Fix/Improvement: Pipelines ensure that when part of the information is persisted, all necessary pieces to load that information are also persisted
Improvement: re-do the persist-at-shutdown behavior to be more robust
Improvement: even if one Pipeline fails to persist at shutdown, allow other Pipelines to attempt to persist
Fix: A variety of synchronization consistency problems
Improvement: Rewrite handling of missing FlowNodeStorage and creation of placeholder nodes to ensure correctness and done state is persisted
Fix: Pipelines blocking restart of Jenkins masters if they failed to resume or threw an exception when loading the Pipeline program
Fix: Pipeline builds showing as incomplete when they failed to resume or load
Greatly expanded test coverage for persistence and edge-cases where incorrect data is persisted

2.49

Release date: 2018-04-20

Bugfix: Solve Replay not being visible or usable for builds (regression from lazy load of executions introduced in workflow-job) (JENKINS-50874)
Bugfix: CpsScript invokeMethod does not execute closures defined in the script binding.
Maintenance: Stop using the Junit Step in Metastep tests (prevents Plugin Compatibility Test failurs)

2.48

Release date: 2018-04-12

Bugfix: FlowNode Serialization Could Fail Due to Unserializable Step Arguments (JENKINS-50752)
- This could trigger deeper failures in Pipeline due to the serialization failures before workflow-api 2.27

2.47

Release date: 2018-04-08

Major bugfix / improvements: numerous fixes & improvements to make Pipeline persistence & resume more robust (across all Durability Settings)
- These do not have individual JIRAs because they were spinoffs from testing other work, discovered with fuzzing-like approaches
- Many of these bugs would result in irreproducible errors that may have been reported - link any related JIRAs here: (TBD)
- Improves error-handling logic
Part of Major Bugfix: Error "NullPointerException in CPS VM thread at WorkflowRun$GraphL.onNewHead" as result of a race condition (JENKINS-49686)
- The other part of the bugfix is in the Pipeline Job Plugin - version 2.18
Part of Major Bugfix: Failed pipelines resume and won't die even when marked to not resume, and show resume failures (JENKINS-50199)
- The other part of the bugfix is in the Pipeline Job Plugin - version 2.18
Part of Bugfix: Error "NullPointerException in SandboxContinuable.run0" after restart in Performance-Optimized Durability Setting (JENKINS-50407)
- The other part of the bugfix is in the Pipeline Job Plugin - version 2.18

2.46

Release date: 2018-04-05

JENKINS-45575, JENKINS-49679 - Fix a couple issues with multiple assignment.
JENKINS-49961 - Fix an NPE when toggling ResumeEnabled when FlowExecutionOwner is not yet set.
JENKINS-45982 - Fix calling a CPS-transformed super.
JENKINS-33614 - Include link to script approval for RejectedAccessException - but only when the user viewing the console has permissions for script approval.
JENKINS-50171 - Avoid LinkageError with load step of Groovy files with a package declaration on resume of Pipeline.

2.45

Release date: 2018-02-14

Enhancement: Improve performance of running pipelines - reduce CPU, wall time, and disk IO.
- Works by eliminating reflection and classloading needed to determine how many arguments a Step needs
Enhancement: In Snippetizer, support Symbol use with different lists of inputs to steps (JENKINS-37215)
Misc: Pick up more modern structs, and reduce memory garbage for steps slightly by using DescribableModel.of API

2.44

Release date: 2018-01-31

Pick up recent groovy-cps fixes including resolving a quirk with field initialization and CPS transforms
Implement support for SCM retry count - JENKINS-39194

2.43

Release date: 2018-01-22

Major Feature: Support for faster Durability Settings which reduce I/O and improve performance significantly (JENKINS-47300)
Major Feature: ability to disable Pipeline auto-resume when restarting (JENKINS-33761)
Major Feature: consolidate writing FlowNodes using granular persistence APIs (JENKINS-47172)
Robustness Enhancement: a giant wad of fixes to ensure we handle persistence failures and oddball circumstances
- Extensive test coverage, plus protects against some "hung" pipeline states and other weird bugs
Enhancement: reduce memory used by Pipeline for storing Step arguments (PR #65)
Bugfix: first Pipeline step lacks displayed arguments (JENKINS-48644)

2.42

Release date: 2017-11-29

Compatibility Note: this is the first version requiring Java 8 (Jenkins LTS 2.60.x+)
JENKINS-44619 - Don't allow replaying unbuildable jobs
Rename ReplayCommand to ReplayPipelineCommand
JENKINS-47339 - Allow users with Build permission but not Configure permission to replay a build with the same script.
JENKINS-46597 - Fix IteratorHack to handle SortedMap, like TreeMap, without serialization issues.
Protect against unlimited recursion with a sane error.

2.41

Release date: 2017-09-28

JENKINS-47071 - Allow .every, .any, and other closure methods involving booleans to serialize properly.
Reduce memory of CPS code significantly by lazily initializing locals maps
JENKINS-44027 - Support multiple assignment in Pipeline scripts
JENKINS-32213 - Automatically make all CPS-transformed classes Serializable, no longer requiring that to be done explicitly.
Do not even offer PauseUnpauseAction unless you actually have CANCEL permissions

2.40

Release date: 2017-09-05

JENKINS-34645 - Serialize array iterators properly
JENKINS-46391 - Correctly translate ~/foo/ as a regexp
JENKINS-46358 - Support for a number of StringGroovyMethods

2.39 (Aug 7, 2017)

Release date: 2017-08-07

Fixes for multiple security issues in script security plugin

2.38

Release date: 2017-08-01

JENKINS-44548 Fix NullPointerException caused by corrupted FlowExecution records

2.37

Release date: 2017-07-25

Robustness fix involving StepContext.get(FlowNode) calls.
JENKINS-45109 Metastep display improvements useful especially for step and wrap calls in Blue Ocean.
JENKINS-31582 API for obtaining step arguments in more realistic form.
Improved logging of @script checkout.

2.36.1

Release date: 2017-07-10

Fix security issue

2.36

Release date: 2017-06-15

Enabling whitelist entries to work for most Groovy built-in methods enabled in 2.33.
Timeouts in CpsFlowExecution.suspendAll could block Jenkins shutdown.

2.35

Release date: 2017-06-13

[38268@issue] Improper binding of local variables in closures.
Functional tests sometimes failed due to DSL finding no step definitions.

2.34

Release date: 2017-06-03

JENKINS-44578 Corrects a StackOverflowError seen on some JVMs with limited stack size running Declarative Pipelines after updating to 2.33.

2.33 (May 30, 2017)

Release date: 2017-05-30

Requires Jenkins 2.7.x or later.

Warning: GROOVY-6263 will affect Jenkins installations until Groovy 2.5.0 is integrated. Briefly, private methods may not be visible if called from an instance of a subclass of the class defining the method. The workaround is to relax the access restriction, for example to protected.

Users of Declarative Pipeline should update to 2.34.

JENKINS-26481 Most Groovy built-in methods taking closures (such as List.each) may now be used from Pipeline script without @NonCPS annotations. Certain less commonly used methods (such as sort taking a closure) are not yet implemented.
JENKINS-27421 Most Java methods returning iterators (such as looping over the result of Map.entrySet) may now be used from Pipeline script without @NonCPS annotations.
JENKINS-31967 Pipeline Syntax support for double values, as in the junit step for example.
JENKINS-43055 GraphListener may now be used as an extension point.

2.32

Release date: 2017-05-24

Timing feature in 2.31 introduced a memory leak when using shared libraries.

2.31

Release date: 2017-05-22

JENKINS-37324 Store and display arguments supplied to steps
JENKINS-44406 Fix a NullPointerException from StepDescriptorCache when the plugin providing the Step is uninstalled
Record timing information for various internal operations in Pipeline builds, available when support-core is installed.
Deleting program.dat when a build finishes.

2.30

Release date: 2017-04-24

Robustness fix related to JENKINS-26137.
JENKINS-43361 Unreproducible NullPointerException.
JENKINS-43019 ClassCastException under certain circumstances involving libraries.

2.29

Release date: 2017-03-03

Pulls in SCM API Plugin 2.x; read this blog post.

JENKINS-33273 New option for script-from-SCM jobs to load the script directly, rather than performing a full checkout. Requires a compatible SCM, currently Git. Enabled by default for new jobs (falls back to heavyweight checkout where necessary).
JENKINS-42367 NullPointerException using params when certain kinds of parameter values were missing.

2.28

Release date: 2017-02-23

JENKINS-42189 Problems in memory cleanup when using Groovy 2.4.8 (Jenkins 2.47+) could lead to deadlocks and/or large heap consumption.
Flow node IDs incorrectly skipped even numbers after around 500.

2.27

Release date: 2017-02-13

JENKINS-41945 NullPointerException during build cleanup, and consequent memory leak, under heavy load.
JENKINS-32986 Apply timeouts to some operations in the CPS VM thread.
Ensure build terminates after certain internal errors.

2.26

Release date: 2017-02-07

Pull in workflow-api 1.10 and refactor StepNode so that libraries can obtain Step info without depending on workflow-cps

2.25

Release date: 2017-02-01

JENKINS-39719 Cryptic error about overriding methods named like ___cps___2 under certain conditions involving global libraries.
JENKINS-31484 Incorrect CPS translation of field references from getters and setters could lead to endless loops.

2.24

Release date: 2017-01-17

Reducing frequency of program.dat saves, avoiding some otherwise harmless serialization errors, and possibly improving performance for builds with complex Groovy logic.
Correcting two kinds of NullPointerException when loading old build records.
JENKINS-29656 Avoid failing the build merely because renaming a temporary file to program.dat fails, typically on Windows due to file locks from antivirus scanners.
JENKINS-38551 Invalid characters in GDSL.
Performance improvement related to StepDescriptor.

2.23 (Nov 07, 2016)

Release date: 2016-11-07

Fixed a number of memory leaks, extending fixes made in 2.12.
JENKINS-39456 Reduce memory footprint from graph of execution.
Language fixes, including support for:
- super.method(…) calls
- abstract methods
- list to constructor coercion

2.22

Release date: 2016-11-01

Bug fix required for proper display of JENKINS-28385 in step reference.
JENKINS-39275 Cap the amount of time spent displaying one line of a virtual thread dump.
Text changes in Pipeline Syntax page.

2.21

Release date: 2016-10-21

JENKINS-39154 In-browser Pipeline script editor was broken in 2.20.

2.20

Release date: 2016-10-20

Warning: Do not use: see 2.21

JENKINS-34637 timeout did not work when using most nested block steps.
Improved behavior on NotSerializableException such as in JENKINS-27421.

2.19

Release date: 2016-10-11

Addresses some issues related to params encountered in 2.18. In particular, a simple params.paramName now suffices to obtain a parameter including a fallback to its default value even in the first build of a branch project using properties.

JENKINS-35698 params now honors currently defined parameter definition defaults.
Global variables now take precedence over environment variables in case of ambiguity.
Clarifying and enforcing that params is read-only.

2.18

Release date: 2016-09-23

You should also update the Pipeline Job Plugin to 2.7 or later, so that build parameters are defined as environment variables and thus accessible as if they were global Groovy variables.

Beware that binding['parameter.with-funny+characters'] will no longer work; use params['parameter.with-funny+characters'] instead. Also note that buildParameterName = 'new-value' will not work, since the fallback to env currently takes precedence over global variable bindings; better to treat build parameters as read-only and introduce a new local variable with def.

Similarly, if using ParametersDefinitionProperty from properties in a multibranch Jenkinsfile (including via the symbol parameters in Jenkins 2.x), the trick
binding.hasVariable('paramName') ? paramName : 'fallback'
for accessing the parameter value with a fallback in the initial build no longer works. You can now use the simpler
params.paramName ?: 'fallback'
or to maintain compatibility with installations with or without these changes:
env.paramName ?: binding.hasVariable('paramName') ? paramName : 'fallback'

JENKINS-29952 env.PROP may now be shortened simply to PROP when unambiguous. (Setting a variable still requires the prefix, or the withEnv step.)
JENKINS-27295 Build parameters may now be accessed via the params global variable, with typed values.
JENKINS-38114 currentBuild global variable documentation now displayed in full, rather than referring to build step documentation; and updated to better explain usage in light of changes in 2.14.
Unreproducible case of an error during build abort handling of a step making the build not abort cleanly.
Fixed a certain class of build hangs due to code mistakes, and improved error reporting for these cases.
Improved display in the build log of predictable problems resuming a build, such as cancellation of queue items for offline agents inside a node block.
Adding HTML anchors to the Global Variable Reference for easier linking.

2.17

Release date: 2016-09-13

JENKINS-38169 Regression in 2.14 affecting certain steps with a single parameter.

2.16