diff --git a/build.gradle.kts b/build.gradle.kts
index 3c07ae0a9e8..a1dfb181225 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -63,7 +63,7 @@ val kotlinVersion by extra(
         } ?: buildNumber
 )
 
-val kotlinLanguageVersion by extra("1.5")
+val kotlinLanguageVersion by extra("1.6")
 
 allprojects {
     group = "org.jetbrains.kotlin"
diff --git a/compiler/fir/resolve/build.gradle.kts b/compiler/fir/resolve/build.gradle.kts
index f464ea627fe..11326ca7eee 100644
--- a/compiler/fir/resolve/build.gradle.kts
+++ b/compiler/fir/resolve/build.gradle.kts
@@ -19,3 +19,13 @@ sourceSets {
     "main" { projectDefault() }
     "test" { none() }
 }
+
+tasks {
+    val compileKotlin by existing(org.jetbrains.kotlin.gradle.tasks.KotlinCompile::class) {
+        kotlinOptions {
+            // Workaround for KT-48445.
+            languageVersion = "1.5"
+            apiVersion = "1.5"
+        }
+    }
+}
diff --git a/gradle/verification-metadata.xml b/gradle/verification-metadata.xml
index 4b721cc8973..556f0013621 100644
--- a/gradle/verification-metadata.xml
+++ b/gradle/verification-metadata.xml
@@ -7383,10 +7383,10 @@
             <sha256 value="7a6bd3e09a63d6a57725cc3016465d2148b8febb82a6b165b33956f8a15e0b94" origin="Generated by Gradle"/>
          </artifact>
       </component>
-      <component group="org.jetbrains.kotlinx" name="binary-compatibility-validator" version="0.5.0">
-         <artifact name="binary-compatibility-validator-0.5.0.jar">
-            <md5 value="182080d1b43bf3328ad1566dd732780f" origin="Generated by Gradle"/>
-            <sha256 value="7febe38bd39cce08705c7d5b86b8ae369acaca64b54ca2ffc5211399efbc48f1" origin="Generated by Gradle"/>
+      <component group="org.jetbrains.kotlinx" name="binary-compatibility-validator" version="0.7.1">
+         <artifact name="binary-compatibility-validator-0.7.1.jar">
+            <md5 value="f188e849f683da58684012bbdc732abc" origin="Generated by Gradle"/>
+            <sha256 value="d6c3b8d52ae3653375140d67e859477ef90d193be48d44486b21efd70fa2eedc" origin="Generated by Gradle"/>
          </artifact>
       </component>
       <component group="org.jetbrains.kotlinx" name="kotlinx-benchmark-plugin" version="0.3.1">
diff --git a/libraries/tools/binary-compatibility-validator/build.gradle b/libraries/tools/binary-compatibility-validator/build.gradle
index 8e86b92cb99..9341a9be191 100644
--- a/libraries/tools/binary-compatibility-validator/build.gradle
+++ b/libraries/tools/binary-compatibility-validator/build.gradle
@@ -6,7 +6,7 @@ configurations {
 }
 
 dependencies {
-    compile("org.jetbrains.kotlinx:binary-compatibility-validator:0.5.0")
+    compile("org.jetbrains.kotlinx:binary-compatibility-validator:0.7.1")
 
     testCompile project(':kotlin-test:kotlin-test-junit')
 
diff --git a/libraries/tools/binary-compatibility-validator/reference-public-api/kotlin-stdlib-runtime-merged.txt b/libraries/tools/binary-compatibility-validator/reference-public-api/kotlin-stdlib-runtime-merged.txt
index a38b1051d3a..407fa7b4f40 100644
--- a/libraries/tools/binary-compatibility-validator/reference-public-api/kotlin-stdlib-runtime-merged.txt
+++ b/libraries/tools/binary-compatibility-validator/reference-public-api/kotlin-stdlib-runtime-merged.txt
@@ -605,7 +605,6 @@ public abstract class kotlin/collections/AbstractIterator : java/util/Iterator,
 }
 
 public abstract class kotlin/collections/AbstractList : kotlin/collections/AbstractCollection, java/util/List, kotlin/jvm/internal/markers/KMappedMarker {
-	public static final field Companion Lkotlin/collections/AbstractList$Companion;
 	protected fun <init> ()V
 	public fun add (ILjava/lang/Object;)V
 	public fun addAll (ILjava/util/Collection;)Z
@@ -624,7 +623,6 @@ public abstract class kotlin/collections/AbstractList : kotlin/collections/Abstr
 }
 
 public abstract class kotlin/collections/AbstractMap : java/util/Map, kotlin/jvm/internal/markers/KMappedMarker {
-	public static final field Companion Lkotlin/collections/AbstractMap$Companion;
 	protected fun <init> ()V
 	public fun clear ()V
 	public fun containsKey (Ljava/lang/Object;)Z
@@ -685,7 +683,6 @@ public abstract class kotlin/collections/AbstractMutableSet : java/util/Abstract
 }
 
 public abstract class kotlin/collections/AbstractSet : kotlin/collections/AbstractCollection, java/util/Set, kotlin/jvm/internal/markers/KMappedMarker {
-	public static final field Companion Lkotlin/collections/AbstractSet$Companion;
 	protected fun <init> ()V
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
@@ -693,7 +690,6 @@ public abstract class kotlin/collections/AbstractSet : kotlin/collections/Abstra
 }
 
 public final class kotlin/collections/ArrayDeque : kotlin/collections/AbstractMutableList {
-	public static final field Companion Lkotlin/collections/ArrayDeque$Companion;
 	public fun <init> ()V
 	public fun <init> (I)V
 	public fun <init> (Ljava/util/Collection;)V
diff --git a/libraries/tools/binary-compatibility-validator/src/test/kotlin/cases/companions/companions.txt b/libraries/tools/binary-compatibility-validator/src/test/kotlin/cases/companions/companions.txt
index a58446d2a6f..6ceab6c5c92 100644
--- a/libraries/tools/binary-compatibility-validator/src/test/kotlin/cases/companions/companions.txt
+++ b/libraries/tools/binary-compatibility-validator/src/test/kotlin/cases/companions/companions.txt
@@ -27,7 +27,6 @@ protected final class cases/companions/PublicClasses$AbstractProtectedCompanion$
 }
 
 public final class cases/companions/PublicClasses$InternalCompanion {
-	public static final field Companion Lcases/companions/PublicClasses$InternalCompanion$Companion;
 	public fun <init> ()V
 }
 
@@ -52,7 +51,6 @@ public final class cases/companions/PublicInterfaces {
 }
 
 public abstract interface class cases/companions/PublicInterfaces$PrivateCompanion {
-	public static final synthetic field Companion Lcases/companions/PublicInterfaces$PrivateCompanion$Companion;
 }
 
 public abstract interface class cases/companions/PublicInterfaces$PublicCompanion {