diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 406baf9a9..6ef547589 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -17,7 +17,7 @@ jobs:
         java: [ 8, 11 ]
         # WARN: build.sbt depends on this key path, as scalaVersion and
         # crossScalaVersions is determined from it
-        scala: [ 2.12.15, 2.13.8, 3.1.2 ]
+        scala: [ 2.13.8, 3.1.2 ]
 
     env:
       CI: true
diff --git a/build.sbt b/build.sbt
index ab1241bd5..4b40b98db 100644
--- a/build.sbt
+++ b/build.sbt
@@ -376,7 +376,8 @@ def mimaSettings(projectName: String) = Seq(
   mimaBinaryIssueFilters ++= MimaFilters.changesFor_3_0_1,
   mimaBinaryIssueFilters ++= MimaFilters.changesFor_3_2_0,
   mimaBinaryIssueFilters ++= MimaFilters.changesFor_3_3_0,
-  mimaBinaryIssueFilters ++= MimaFilters.changesFor_3_4_0
+  mimaBinaryIssueFilters ++= MimaFilters.changesFor_3_4_0,
+  mimaBinaryIssueFilters ++= MimaFilters.changesFor_avs
 )
 
 lazy val doctestTestSettings = Seq(
diff --git a/monix-execution/shared/src/main/scala_2.13-/monix/execution/compat.scala b/monix-execution/shared/src/main/scala_2.13-/monix/execution/compat.scala
deleted file mode 100644
index 44487e7a3..000000000
--- a/monix-execution/shared/src/main/scala_2.13-/monix/execution/compat.scala
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- * Copyright (c) 2014-2021 by The Monix Project Developers.
- * See the project homepage at: https://monix.io
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package monix.execution
-
-import scala.collection.generic.CanBuildFrom
-import scala.collection.mutable
-
-object compat {
-
-  type BuildFrom[-From, -A, +C] = CanBuildFrom[From, A, C]
-
-  private[monix] object internal {
-    type IterableOnce[+X] = scala.collection.GenTraversableOnce[X]
-    def toIterator[X](i: IterableOnce[X]): Iterator[X] = i.toIterator
-    def hasDefiniteSize[X](i: IterableOnce[X]): Boolean = i.hasDefiniteSize
-
-    def newBuilder[From, A, C](bf: BuildFrom[From, A, C], from: From): mutable.Builder[A, C] = bf.apply(from)
-
-    def toSeq[A](array: Array[AnyRef]): Seq[A] =
-      new scala.collection.mutable.WrappedArray.ofRef(array).toSeq.asInstanceOf[Seq[A]]
-  }
-
-  private[monix] object Features {
-    type Flag <: Long with monix.execution.Features.FlagTag
-
-    type Flags <: Long with monix.execution.Features.FlagsTag
-  }
-}
diff --git a/project/MimaFilters.scala b/project/MimaFilters.scala
index 491aa12a2..48a1ae9f5 100644
--- a/project/MimaFilters.scala
+++ b/project/MimaFilters.scala
@@ -100,4 +100,11 @@ object MimaFilters {
     // Scala 3 / Dotty support
     exclude[MissingClassProblem]("monix.execution.schedulers.AdaptedThreadPoolExecutorMixin")
   )
+
+  lazy val changesFor_avs = Seq(
+    // TrampolineExecutionContext signature tweaks (internal API)
+    exclude[IncompatibleMethTypeProblem]("monix.execution.schedulers.TrampolineExecutionContext#JVMNormalTrampoline.startLoop"),
+    exclude[IncompatibleMethTypeProblem]("monix.execution.schedulers.TrampolineExecutionContext#JVMOptimalTrampoline.startLoop"),
+    exclude[IncompatibleMethTypeProblem]("monix.execution.schedulers.TrampolineExecutionContext.this")
+  )
 }