diff --git a/akka-remote/src/main/scala/akka/remote/Endpoint.scala b/akka-remote/src/main/scala/akka/remote/Endpoint.scala
index 99b1347f70..b446b0276b 100644
--- a/akka-remote/src/main/scala/akka/remote/Endpoint.scala
+++ b/akka-remote/src/main/scala/akka/remote/Endpoint.scala
@@ -496,7 +496,7 @@ private[remote] class ReliableDeliverySupervisor(
       // If we have not confirmed the remote UID we cannot transfer the system message at this point just buffer it.
       // GotUid will kick resendAll() causing the messages to be properly written.
       // Flow control by not sending more when we already have many outstanding.
-      if (uidConfirmed && resendBuffer.nonAcked.size <= settings.SysResendLimit)
+      if (uidConfirmed && resendBuffer.nonAcked.length <= settings.SysResendLimit)
         writer ! sequencedSend
     } else writer ! send
 
@@ -1130,7 +1130,7 @@ private[remote] class EndpointReader(
   override def receive: Receive = {
     case Disassociated(info) => handleDisassociated(info)
 
-    case InboundPayload(p) if p.size <= transport.maximumPayloadBytes =>
+    case InboundPayload(p) if p.length <= transport.maximumPayloadBytes =>
       val (ackOption, msgOption) = tryDecodeMessageAndAck(p)
 
       for (ack <- ackOption; reliableDelivery <- reliableDeliverySupervisor) reliableDelivery ! ack
@@ -1180,7 +1180,7 @@ private[remote] class EndpointReader(
     case StopReading(writer, replyTo) =>
       replyTo ! StoppedReading(writer)
 
-    case InboundPayload(p) if p.size <= transport.maximumPayloadBytes =>
+    case InboundPayload(p) if p.length <= transport.maximumPayloadBytes =>
       val (ackOption, msgOption) = tryDecodeMessageAndAck(p)
       for (ack <- ackOption; reliableDelivery <- reliableDeliverySupervisor) reliableDelivery ! ack
 
diff --git a/akka-remote/src/main/scala/akka/remote/artery/tcp/TcpFraming.scala b/akka-remote/src/main/scala/akka/remote/artery/tcp/TcpFraming.scala
index 5f7b0bb7d0..1594ae499a 100644
--- a/akka-remote/src/main/scala/akka/remote/artery/tcp/TcpFraming.scala
+++ b/akka-remote/src/main/scala/akka/remote/artery/tcp/TcpFraming.scala
@@ -69,7 +69,7 @@ import akka.util.ByteString
 
     case object ReadMagic extends Step {
       override def parse(reader: ByteReader): ParseResult[EnvelopeBuffer] = {
-        val magic = reader.take(TcpFraming.Magic.size)
+        val magic = reader.take(TcpFraming.Magic.length)
         if (magic == TcpFraming.Magic)
           ParseResult(None, ReadStreamId)
         else
diff --git a/akka-stream/src/main/scala/akka/stream/impl/io/ByteStringParser.scala b/akka-stream/src/main/scala/akka/stream/impl/io/ByteStringParser.scala
index fd5c122daa..52578b0a2a 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/io/ByteStringParser.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/io/ByteStringParser.scala
@@ -185,8 +185,8 @@ import akka.util.ByteString
 
     private[this] var off = 0
 
-    def hasRemaining: Boolean = off < input.size
-    def remainingSize: Int = input.size - off
+    def hasRemaining: Boolean = off < input.length
+    def remainingSize: Int = input.length - off
 
     def currentOffset: Int = off
 
diff --git a/akka-stream/src/main/scala/akka/stream/impl/io/compression/DeflateCompressor.scala b/akka-stream/src/main/scala/akka/stream/impl/io/compression/DeflateCompressor.scala
index a904232c8e..f7cf90e0de 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/io/compression/DeflateCompressor.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/io/compression/DeflateCompressor.scala
@@ -19,12 +19,12 @@ import akka.util.{ ByteString, ByteStringBuilder }
   protected lazy val deflater = new Deflater(level, nowrap)
 
   override final def compressAndFlush(input: ByteString): ByteString = {
-    val buffer = newTempBuffer(input.size)
+    val buffer = newTempBuffer(input.length)
 
     compressWithBuffer(input, buffer) ++ flushWithBuffer(buffer)
   }
   override final def compressAndFinish(input: ByteString): ByteString = {
-    val buffer = newTempBuffer(input.size)
+    val buffer = newTempBuffer(input.length)
 
     compressWithBuffer(input, buffer) ++ finishWithBuffer(buffer)
   }
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Framing.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Framing.scala
index e03efa0084..cf3f57b112 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Framing.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Framing.scala
@@ -265,27 +265,27 @@ object Framing {
                 s"Read ${possibleMatchPos - previous} bytes " +
                 s"which is more than $maximumLineBytes without seeing a line terminator"))
           } else if (possibleMatchPos == -1) {
-            if (buffer.size - previous > maximumLineBytes)
+            if (buffer.length - previous > maximumLineBytes)
               failStage(
                 new FramingException(
-                  s"Read ${buffer.size - previous} bytes " +
+                  s"Read ${buffer.length - previous} bytes " +
                   s"which is more than $maximumLineBytes without seeing a line terminator"))
             else {
               // No matching character, we need to accumulate more bytes into the buffer
-              nextPossibleMatch = buffer.size
+              nextPossibleMatch = buffer.length
               doParse()
             }
-          } else if (possibleMatchPos + separatorBytes.size > buffer.size) {
+          } else if (possibleMatchPos + separatorBytes.length > buffer.length) {
             // We have found a possible match (we found the first character of the terminator
             // sequence) but we don't have yet enough bytes. We remember the position to
             // retry from next time.
             nextPossibleMatch = possibleMatchPos
             doParse()
-          } else if (buffer.slice(possibleMatchPos, possibleMatchPos + separatorBytes.size) == separatorBytes) {
+          } else if (buffer.slice(possibleMatchPos, possibleMatchPos + separatorBytes.length) == separatorBytes) {
             // Found a match, mark start and end position and iterate if possible
             indices += (previous -> possibleMatchPos)
-            nextPossibleMatch = possibleMatchPos + separatorBytes.size
-            if (nextPossibleMatch == buffer.size || indices.isFull) {
+            nextPossibleMatch = possibleMatchPos + separatorBytes.length
+            if (nextPossibleMatch == buffer.length || indices.isFull) {
               doParse()
             } else {
               searchIndices()