diff --git a/build.sbt b/build.sbt
index ef3d2f67..c4e1a160 100644
--- a/build.sbt
+++ b/build.sbt
@@ -55,11 +55,12 @@ def commonSettings: Seq[Setting[_]] = Def.settings(
   scalacOptions := {
     val old = scalacOptions.value
     scalaVersion.value match {
-      case sv if sv.startsWith("2.10") =>
-        old diff List("-Xfuture", "-Ywarn-unused", "-Ywarn-unused-import")
-      case sv if sv.startsWith("2.11") => old ++ List("-Ywarn-unused", "-Ywarn-unused-import")
       case sv if sv.startsWith("2.12") =>
-        old ++ List("-Ywarn-unused", "-Ywarn-unused-import", "-YdisableFlatCpCaching")
+        old ++ List(
+          "-Ywarn-unused",
+          "-Ywarn-unused-import",
+          "-Ywarn-unused:-nowarn",
+        )
       case _ => old
     }
   },
diff --git a/core/src/main/scala/sbt/internal/librarymanagement/cross/CrossVersionUtil.scala b/core/src/main/scala/sbt/internal/librarymanagement/cross/CrossVersionUtil.scala
index eef2d1a2..f2d46713 100644
--- a/core/src/main/scala/sbt/internal/librarymanagement/cross/CrossVersionUtil.scala
+++ b/core/src/main/scala/sbt/internal/librarymanagement/cross/CrossVersionUtil.scala
@@ -117,7 +117,13 @@ object CrossVersionUtil {
   }
 
   def binarySbtVersion(full: String): String =
-    binaryVersionWithApi(full, TransitionSbtVersion)(sbtApiVersion)
+    sbtApiVersion(full) match {
+      case Some((0, minor)) if minor < 12 => full
+      case Some((0, minor))               => s"0.$minor"
+      case Some((1, minor))               => s"1.$minor"
+      case Some((major, _))               => major.toString
+      case _                              => full
+    }
 
   private[this] def isNewer(major: Long, minor: Long, minMajor: Long, minMinor: Long): Boolean =
     major > minMajor || (major == minMajor && minor >= minMinor)
diff --git a/core/src/test/scala/sbt/librarymanagement/CrossVersionTest.scala b/core/src/test/scala/sbt/librarymanagement/CrossVersionTest.scala
index 96b3d164..c273653a 100644
--- a/core/src/test/scala/sbt/librarymanagement/CrossVersionTest.scala
+++ b/core/src/test/scala/sbt/librarymanagement/CrossVersionTest.scala
@@ -96,23 +96,23 @@ class CrossVersionTest extends UnitSpec {
   "binarySbtVersion" should "for 0.11.3 return 0.11.3" in {
     binarySbtVersion("0.11.3") shouldBe "0.11.3"
   }
-  it should "for 0.12.0-M1 return 0.12.0-M1" in {
-    binarySbtVersion("0.12.0-M1") shouldBe "0.12.0-M1"
+  it should "for 2.0.0 return 2" in {
+    binarySbtVersion("2.0.0") shouldBe "2"
   }
-  it should "for 0.12.0-RC1 return 0.12" in {
-    binarySbtVersion("0.12.0-RC1") shouldBe "0.12"
+  it should "for 2.0.0-M1 return 2.0.0-M1" in {
+    binarySbtVersion("2.0.0-M1") shouldBe "2.0.0-M1"
   }
-  it should "for 0.12.0 return 0.12" in {
-    binarySbtVersion("0.12.0") shouldBe "0.12"
+  it should "for 2.0.0-RC1 return 2" in {
+    binarySbtVersion("2.0.0-RC1") shouldBe "2"
   }
-  it should "for 0.12.1-SNAPSHOT return 0.12" in {
-    binarySbtVersion("0.12.1-SNAPSHOT") shouldBe "0.12"
+  it should "for 2.1.0-M1 return 2" in {
+    binarySbtVersion("2.1.0-M1") shouldBe "2"
   }
-  it should "for 0.12.1-RC1 return 0.12" in {
-    binarySbtVersion("0.12.1-RC1") shouldBe "0.12"
+  it should "for 2.1.0 return 2" in {
+    binarySbtVersion("2.1.0") shouldBe "2"
   }
-  it should "for 0.12.1 return 0.12" in {
-    binarySbtVersion("0.12.1") shouldBe "0.12"
+  it should "for 0.13.1 return 0.13" in {
+    binarySbtVersion("0.13.1") shouldBe "0.13"
   }
   it should "for 1.0.0-M6 return 1.0.0-M6" in {
     binarySbtVersion("1.0.0-M6") shouldBe "1.0.0-M6"
@@ -144,9 +144,6 @@ class CrossVersionTest extends UnitSpec {
   it should "for 1.10.0 return 1.0" in {
     binarySbtVersion("1.10.0") shouldBe "1.0"
   }
-  it should "for 2.0.0 return 2.0" in {
-    binarySbtVersion("2.0.0") shouldBe "2.0"
-  }
 
   "scalaApiVersion" should "for xyz return None" in {
     scalaApiVersion("xyz") shouldBe None