diff --git a/CHANGELOG.md b/CHANGELOG.md
index d62754db..459f1c1f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Extracted Git-based versioning into a separate subproject, `git-based-versioning`.
+- `runMigrations`: `force` and `haltOnPrecheckFailure` are now nullable and null by default.
 
 ## 1.15
 
diff --git a/build.gradle.kts b/build.gradle.kts
index 0d59590b..94cea2f3 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -29,12 +29,12 @@ val versionMinor = 16
 group = "de.itemis.mps"
 
 var currentBranch:String? = ""
-currentBranch = de.itemis.mps.gradle.GitBasedVersioning.getGitBranch()
+currentBranch = GitBasedVersioning.getGitBranch()
 
 version = if (!project.hasProperty("useSnapshot") &&
     (project.hasProperty("forceCI") || project.hasProperty("teamcity"))
 ) {
-    de.itemis.mps.gradle.GitBasedVersioning.getVersion(
+    GitBasedVersioning.getVersion(
         // Publish releases from v1.x branch without v1.x prefix
         if (currentBranch == "v1.x") "HEAD" else currentBranch,
         versionMajor.toString(), versionMinor.toString())
diff --git a/src/main/kotlin/de/itemis/mps/gradle/runmigrations/Plugin.kt b/src/main/kotlin/de/itemis/mps/gradle/runmigrations/Plugin.kt
index 07421e00..40674987 100644
--- a/src/main/kotlin/de/itemis/mps/gradle/runmigrations/Plugin.kt
+++ b/src/main/kotlin/de/itemis/mps/gradle/runmigrations/Plugin.kt
@@ -18,13 +18,13 @@ open class MigrationExecutorPluginExtensions @Inject constructor(of: ObjectFacto
      * (Since MPS 2021.1) Whether to halt if a pre-check has failed. Note that the check for migrated dependencies
      * cannot be skipped.
      */
-    var haltOnPrecheckFailure = true
+    var haltOnPrecheckFailure: Boolean? = null
 
     /**
      * (Since MPS 2021.3) Whether to force a migration even if the project directory contains `.allow-pending-migrations` file.
      */
 
-    var force = false
+    var force: Boolean? = null
 }
 
 @Suppress("unused")
@@ -49,11 +49,11 @@ open class RunMigrationsMpsProjectPlugin : Plugin<Project> {
                 val mpsVersion = extension.getMPSVersion()
                 val parsedMPSVersion = SemVer.parse(mpsVersion)
 
-                if (extension.force && parsedMPSVersion < MIN_VERSION_FOR_FORCE) {
+                if (extension.force != null && parsedMPSVersion < MIN_VERSION_FOR_FORCE) {
                     throw GradleException("The force migration flag is only supported for MPS version $MIN_VERSION_FOR_FORCE and higher.")
                 }
 
-                if (!extension.haltOnPrecheckFailure && parsedMPSVersion < MIN_VERSION_FOR_HALT_ON_PRECHECK_FAILURE) {
+                if (extension.haltOnPrecheckFailure != null && parsedMPSVersion < MIN_VERSION_FOR_HALT_ON_PRECHECK_FAILURE) {
                     throw GradleException("The 'do not halt on pre-check failure' option is only supported for MPS version $MIN_VERSION_FOR_HALT_ON_PRECHECK_FAILURE and higher.")
                 }
 
@@ -84,8 +84,8 @@ open class RunMigrationsMpsProjectPlugin : Plugin<Project> {
                                 add("project" to projectLocation)
                                 add("mpsHome" to mpsLocation)
 
-                                if (parsedMPSVersion >= MIN_VERSION_FOR_FORCE) add("force" to extension.force)
-                                if (parsedMPSVersion >= MIN_VERSION_FOR_HALT_ON_PRECHECK_FAILURE) add("haltOnPrecheckFailure" to extension.haltOnPrecheckFailure)
+                                if (extension.force != null) add("force" to extension.force!!)
+                                if (extension.haltOnPrecheckFailure != null) add("haltOnPrecheckFailure" to extension.haltOnPrecheckFailure!!)
 
                                 toTypedArray()
                             }