diff --git a/project/Build.scala b/project/Build.scala
index 8f814c7c5206..3dac5b7c2907 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -85,7 +85,7 @@ object Build {
 
   val referenceVersion = "3.3.1"
 
-  val baseVersion = "3.4.0-RC1"
+  val baseVersion = "3.4.1-RC1"
 
   // Versions used by the vscode extension to create a new project
   // This should be the latest published releases.
@@ -101,7 +101,7 @@ object Build {
    *  set to 3.1.3. If it is going to be 3.1.0, it must be set to the latest
    *  3.0.x release.
    */
-  val previousDottyVersion = "3.3.1"
+  val previousDottyVersion = "3.4.0-RC1"
 
   object CompatMode {
     final val BinaryCompatible = 0
@@ -2163,7 +2163,8 @@ object Build {
             (Compile/doc/target).value
           },
           commonMiMaSettings,
-          mimaBinaryIssueFilters ++= MiMaFilters.Library
+          mimaBackwardIssueFilters := MiMaFilters.LibraryBackwards,
+          mimaForwardIssueFilters := MiMaFilters.LibraryForward,
         )
       } else base
     }
diff --git a/project/MiMaFilters.scala b/project/MiMaFilters.scala
index 8a1ea7d1141f..13daebf79adb 100644
--- a/project/MiMaFilters.scala
+++ b/project/MiMaFilters.scala
@@ -2,19 +2,26 @@
 import com.typesafe.tools.mima.core._
 
 object MiMaFilters {
-  val Library: Seq[ProblemFilter] = Seq(
-    // New API in 3.4.X
-    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule#FlagsModule.AbsOverride"),
-    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule.ValOrDefDefTypeTest"),
-    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule.ValOrDefDefMethods"),
-    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule#defnModule.FunctionClass"),
-    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule#defnModule.PolyFunctionClass"),
-    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule#TypeReprMethods.dealiasKeepOpaques"),
-    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule#SymbolMethods.paramVariance"),
-    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule#TypeLambdaMethods.paramVariances"),
+  val LibraryBackwards: Map[String, Seq[ProblemFilter]] = Map(
+    // In general we should never have backwards incompatible changes in the library.
+    // Only exceptional cases should be added here.
+    Build.previousDottyVersion -> Seq(
+      // This language feature was in 3.4.0-RC1 but will be removed in 3.4.0-RC2
+      ProblemFilters.exclude[MissingFieldProblem]("scala.runtime.stdLibPatches.language#deprecated.ascriptionVarargsUnpacking"),
+      ProblemFilters.exclude[MissingClassProblem]("scala.runtime.stdLibPatches.language$deprecated$ascriptionVarargsUnpacking$"),
+    )
+  )
+  val LibraryForward: Map[String, Seq[ProblemFilter]] = Map(
+    // Additions that require a new minor version of the library
+    Build.previousDottyVersion -> Seq(
+      // This language feature is not in 3.4.0-RC1 but will be added in 3.4.0-RC2
+      ProblemFilters.exclude[MissingFieldProblem]("scala.runtime.stdLibPatches.language.3.5-migration"),
+      ProblemFilters.exclude[MissingFieldProblem]("scala.runtime.stdLibPatches.language.3.5"),
+      ProblemFilters.exclude[MissingClassProblem]("scala.runtime.stdLibPatches.language$3$u002E5$"),
+      ProblemFilters.exclude[MissingClassProblem]("scala.runtime.stdLibPatches.language$3$u002E5$minusmigration$"),
+    )
   )
   val TastyCore: Seq[ProblemFilter] = Seq(
-    ProblemFilters.exclude[DirectMissingMethodProblem]("dotty.tools.tasty.TastyFormat.EXPLICITtpt"),
   )
   val Interfaces: Seq[ProblemFilter] = Seq(
   )