diff --git a/akka-distributed-data/src/main/mima-filters/2.5.15.backwards.excludes b/akka-distributed-data/src/main/mima-filters/2.5.15.backwards.excludes
new file mode 100644
index 0000000000..5d12fcc3e3
--- /dev/null
+++ b/akka-distributed-data/src/main/mima-filters/2.5.15.backwards.excludes
@@ -0,0 +1,4 @@
+# #25543 allow BigInt increment and decrements in PNCounter
+ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.cluster.ddata.PNCounter.increment")
+ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.cluster.ddata.PNCounter.decrement")
+ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.cluster.ddata.PNCounter.change")
\ No newline at end of file
diff --git a/akka-distributed-data/src/main/scala/akka/cluster/ddata/PNCounter.scala b/akka-distributed-data/src/main/scala/akka/cluster/ddata/PNCounter.scala
index cb9c2a699d..a6abf1ecf8 100644
--- a/akka-distributed-data/src/main/scala/akka/cluster/ddata/PNCounter.scala
+++ b/akka-distributed-data/src/main/scala/akka/cluster/ddata/PNCounter.scala
@@ -9,6 +9,8 @@ import akka.cluster.UniqueAddress
 import akka.util.HashCode
 import java.math.BigInteger
 
+import akka.annotation.InternalApi
+
 object PNCounter {
   val empty: PNCounter = new PNCounter(GCounter.empty, GCounter.empty)
   def apply(): PNCounter = empty
@@ -122,12 +124,17 @@ final class PNCounter private[akka] (
   def decrement(node: Cluster, n: java.math.BigInteger): PNCounter =
     decrement(node.selfUniqueAddress, n)
 
-  private[akka] def increment(key: UniqueAddress, n: BigInt): PNCounter = change(key, n)
-  private[akka] def increment(key: UniqueAddress): PNCounter = increment(key, 1)
-  private[akka] def decrement(key: UniqueAddress, n: BigInt): PNCounter = change(key, -n)
-  private[akka] def decrement(key: UniqueAddress): PNCounter = decrement(key, 1)
+  /** Internal API */
+  @InternalApi private[akka] def increment(key: UniqueAddress, n: BigInt): PNCounter = change(key, n)
+  /** Internal API */
+  @InternalApi private[akka] def increment(key: UniqueAddress): PNCounter = increment(key, 1)
+  /** Internal API */
+  @InternalApi private[akka] def decrement(key: UniqueAddress, n: BigInt): PNCounter = change(key, -n)
+  /** Internal API */
+  @InternalApi private[akka] def decrement(key: UniqueAddress): PNCounter = decrement(key, 1)
 
-  private[akka] def change(key: UniqueAddress, n: BigInt): PNCounter =
+  /** Internal API */
+  @InternalApi private[akka] def change(key: UniqueAddress, n: BigInt): PNCounter =
     if (n > 0) copy(increments = increments.increment(key, n))
     else if (n < 0) copy(decrements = decrements.increment(key, -n))
     else this