diff --git a/src/com/captainalm/lib/calmnet/marshal/FragmentationOptions.java b/src/com/captainalm/lib/calmnet/marshal/FragmentationOptions.java
index c1aef87..41e2365 100644
--- a/src/com/captainalm/lib/calmnet/marshal/FragmentationOptions.java
+++ b/src/com/captainalm/lib/calmnet/marshal/FragmentationOptions.java
@@ -18,7 +18,7 @@ public final class FragmentationOptions {
      * See:
      * {@link FragmentSender#setSplitSize(int)}
      */
-    public int fragmentationSplitSize = 496;
+    public int fragmentationSplitSize = 448;
     /**
      * See:
      * {@link FragmentReceiver#setNumberOfEmptySendsTillForcedCompleteOrResend(int)}
diff --git a/src/com/captainalm/lib/calmnet/marshal/NetMarshalClient.java b/src/com/captainalm/lib/calmnet/marshal/NetMarshalClient.java
index 590b493..e4b3450 100644
--- a/src/com/captainalm/lib/calmnet/marshal/NetMarshalClient.java
+++ b/src/com/captainalm/lib/calmnet/marshal/NetMarshalClient.java
@@ -101,17 +101,16 @@ public class NetMarshalClient implements Closeable {
             fragmentMonitorThread = new Thread(() -> {
                 int ageCheckTime = this.fragmentationOptions.maximumFragmentAge - 1;
                 while (running) {
-                    int id = -1;
                     synchronized (this.fragmentationOptions) {
                         for (int c : fragmentRMM.keySet()) {
                             if (!fragmentRMM.get(c).plusSeconds(ageCheckTime).isAfter(LocalDateTime.now())) {
-                                fragmentRMM.remove(id);
+                                fragmentRMM.remove(c);
                                 fragmentReceiver.deletePacketFromRegistry(c);
                             }
                         }
                         for (int c : fragmentSMM.keySet()) {
                             if (!fragmentSMM.get(c).plusSeconds(ageCheckTime).isAfter(LocalDateTime.now())) {
-                                fragmentSMM.remove(id);
+                                fragmentSMM.remove(c);
                                 fragmentSender.deletePacketFromRegistry(c);
                             }
                         }
@@ -127,8 +126,8 @@ public class NetMarshalClient implements Closeable {
                 fragmentSMM.clear();
             }, "thread_frag_monitor_" + remoteAddress.getHostAddress() + ":" + remotePort);
             fragmentFinishReceiveMonitorThread = new Thread(() -> {
+                int id = -1;
                 while (running) {
-                    int id = -1;
                     try {
                         while ((id = fragmentReceiver.getLastIDFinished()) != -1) synchronized (this.fragmentationOptions) {
                             fragmentRMM.remove(id);
@@ -139,8 +138,8 @@ public class NetMarshalClient implements Closeable {
                 fragmentReceiver.clearLastIDFinished();
             }, "thread_frag_fin_recv_monitor_" + remoteAddress.getHostAddress() + ":" + remotePort);
             fragmentFinishSendMonitorThread = new Thread(() -> {
+                int id = -1;
                 while (running) {
-                    int id = -1;
                     try {
                         while ((id = fragmentSender.getLastIDFinished()) != -1) synchronized (this.fragmentationOptions) {
                             fragmentSMM.remove(id);
diff --git a/src/com/captainalm/lib/calmnet/packet/PacketLoader.java b/src/com/captainalm/lib/calmnet/packet/PacketLoader.java
index 71067e6..9c49949 100644
--- a/src/com/captainalm/lib/calmnet/packet/PacketLoader.java
+++ b/src/com/captainalm/lib/calmnet/packet/PacketLoader.java
@@ -23,24 +23,41 @@ import static com.captainalm.lib.calmnet.packet.PacketProtocolInformation.savePa
 public class PacketLoader {
     protected boolean allowInvalidPackets;
 
+    protected boolean oldPacketFormat;
+
     /**
      * Constructs a new Packet loader instance.
      * If using a digest provider, use {@link #PacketLoader(DigestProvider)}
      */
     public PacketLoader() {
-        this(null);
+        this(null, false);
     }
 
     /**
      * Constructs a new Packet loader instance with the specified {@link DigestProvider}.
      * If using a digest provider, make sure all endpoints use the same algorithm;
-     * if null, no trailer is created or expected;
+     * if null, no trailer is created;
      * this is ignored if saving / loading packets from byte arrays.
      *
      * @param provider The digest provider or null.
      */
     public PacketLoader(DigestProvider provider) {
+        this(provider, false);
+    }
+
+    /**
+     * Constructs a new Packet loader instance with the specified {@link DigestProvider}
+     * and if the old packet format should be used.
+     * If using a digest provider, make sure all endpoints use the same algorithm;
+     * if null, no trailer is created;
+     * this is ignored if saving / loading packets from byte arrays.
+     *
+     * @param provider The digest provider or null.
+     * @param oldPacketFormat If the old packet format should be used (No explicit hash indication nor length).
+     */
+    public PacketLoader(DigestProvider provider, boolean oldPacketFormat) {
         hashProvider = provider;
+        this.oldPacketFormat = oldPacketFormat;
     }
 
     protected DigestProvider hashProvider;
@@ -72,10 +89,51 @@ public class PacketLoader {
         this.allowInvalidPackets = allowInvalidPackets;
     }
 
+    /**
+     * Is the old packet format in use (No explicit hash indication nor length).
+     *
+     * @return If the old packet format is in use.
+     */
+    public boolean isOldPacketFormatInUse() {
+        return oldPacketFormat;
+    }
+
+    /**
+     * Sets if the old packet format should be used (No explicit hash indication nor length).
+     * @param useOldFormat If the old packet format should be used.
+     */
+    public void setOldPacketFormatUsage(boolean useOldFormat) {
+        oldPacketFormat = useOldFormat;
+    }
+
     protected boolean isPacketInvalid(IPacket packetIn) {
         return (packetIn == null || !packetIn.isValid()) && !allowInvalidPackets;
     }
 
+    /**
+     * Adds the most significant flag to the given integer.
+     *
+     * @param value The integer to add the flag to.
+     * @return The integer with the flag added.
+     */
+    public static int addMostSignificantFlag(int value) {
+        value += 1;
+        value += Integer.MAX_VALUE;
+        return value;
+    }
+
+    /**
+     * Subtracts the most significant flag from the given integer.
+     *
+     * @param value The integer to subtract the flag from.
+     * @return The integer with the flag subtracted.
+     */
+    public static int subtractMostSignificantFlag(int value) {
+        value -= 1;
+        value -= Integer.MAX_VALUE;
+        return value;
+    }
+
     /**
      * Reads a {@link IPacket} from a byte array (No digest support).
      * If the information parameter is null, this is obtained as part of the reading.
@@ -102,8 +160,9 @@ public class PacketLoader {
         if (toret != null) {
             if (arrayIn.length < 6) throw new PacketException("arrayIn does not have a length header.");
             int length = (arrayIn[2] & 0xff) * 16777216 + (arrayIn[3] & 0xff) * 65536 + (arrayIn[4] & 0xff) * 256 + (arrayIn[5] & 0xff);
+            if (length < 0) length = subtractMostSignificantFlag(length);
             byte[] loadArray = new byte[length];
-            System.arraycopy(arrayIn, 6, loadArray, 0, arrayIn.length - 6);
+            System.arraycopy(arrayIn, 6, loadArray, 0, Math.min(arrayIn.length - 6, length));
             toret.loadPayload(loadArray);
             if (isPacketInvalid(toret)) toret = null;
         }
@@ -131,9 +190,23 @@ public class PacketLoader {
         IPacket toret = factory.getPacket(information);
 
         if (toret != null) {
-            InputStream lIS = (hashProvider == null) ? inputStream : hashProvider.getDigestInputStream(inputStream);
-            byte[] loadArray = readArrayFromInputStream(lIS, readInteger(inputStream));
-            if (hashProvider == null || DigestComparer.compareDigests(inputStream, ((DigestInputStream) lIS).getMessageDigest().digest())) toret.loadPayload(loadArray);
+            int length = readInteger(inputStream);
+            boolean hasHash = length < 0;
+            if (hasHash) length = subtractMostSignificantFlag(length);
+            InputStream lIS = (hashProvider == null || !hasHash) ? inputStream : hashProvider.getDigestInputStream(inputStream);
+            byte[] loadArray = readArrayFromInputStream(lIS, length);
+            int hashLength;
+            if (hasHash) {
+                hashLength = readByteIntegerFromInputStream(inputStream);
+                if (hashProvider != null && hashProvider.getLength() != hashLength) {
+                    readArrayFromInputStream(inputStream, hashLength);
+                    return null;
+                }
+            } else hashLength = 0;
+            if ((!hasHash && !oldPacketFormat) || hashProvider == null) {
+                readArrayFromInputStream(inputStream, hashLength);
+                toret.loadPayload(loadArray);
+            } else if (DigestComparer.compareDigests(inputStream, ((DigestInputStream) lIS).getMessageDigest().digest())) toret.loadPayload(loadArray);
             if (isPacketInvalid(toret)) toret = null;
         }
         return toret;
@@ -161,7 +234,9 @@ public class PacketLoader {
         IPacket toret = factory.getPacket(information);
 
         if (toret != null) {
-            byte[] loadArray = readArrayFromInputStream(inputStream, readInteger(inputStream));
+            int length = readInteger(inputStream);
+            if (length < 0) length = subtractMostSignificantFlag(length);
+            byte[] loadArray = readArrayFromInputStream(inputStream, length);
             toret.loadPayload(loadArray);
             if (isPacketInvalid(toret)) toret = null;
         }
@@ -191,9 +266,21 @@ public class PacketLoader {
 
         if (toret instanceof IStreamedPacket) {
             int length = readInteger(inputStream);
-            InputStream lIS = (hashProvider == null) ? inputStream : hashProvider.getDigestInputStream(inputStream);
+            boolean hasHash = length < 0;
+            if (hasHash) length = subtractMostSignificantFlag(length);
+            InputStream lIS = (hashProvider == null || !hasHash) ? inputStream : hashProvider.getDigestInputStream(inputStream);
             ((IStreamedPacket) toret).writeData(lIS, length);
-            if (hashProvider != null && !DigestComparer.compareDigests(inputStream, ((DigestInputStream) lIS).getMessageDigest().digest())) toret = null;
+            int hashLength;
+            if (hasHash) {
+                hashLength = readByteIntegerFromInputStream(inputStream);
+                if (hashProvider != null && hashProvider.getLength() != hashLength) {
+                    readArrayFromInputStream(inputStream, hashLength);
+                    return null;
+                }
+            } else hashLength = 0;
+            if ((hasHash || oldPacketFormat) && hashProvider != null) {
+                if (!DigestComparer.compareDigests(inputStream, ((DigestInputStream) lIS).getMessageDigest().digest())) toret = null;
+            } else readArrayFromInputStream(inputStream, hashLength);
             if (isPacketInvalid(toret)) toret = null;
         } else if (toret != null) {
             return readPacket(inputStream, factory, information);
@@ -225,6 +312,7 @@ public class PacketLoader {
 
         if (toret instanceof IStreamedPacket) {
             int length = readInteger(inputStream);
+            if (length < 0) length = subtractMostSignificantFlag(length);
             ((IStreamedPacket) toret).writeData(inputStream, length);
             if (isPacketInvalid(toret)) toret = null;
         } else if (toret != null) {
@@ -286,15 +374,25 @@ public class PacketLoader {
         if (writeInformation) savePacketProtocolInformation(outputStream, packet.getProtocol());
 
         if (packet instanceof IStreamedPacket) {
-            writeInteger(outputStream, ((IStreamedPacket) packet).getSize());
+            int pLength = ((IStreamedPacket) packet).getSize();
+            if (hashProvider != null && !oldPacketFormat) pLength = addMostSignificantFlag(pLength);
+            writeInteger(outputStream, pLength);
             OutputStream lOS = (hashProvider == null) ? outputStream : hashProvider.getDigestOutputStream(outputStream);
             ((IStreamedPacket) packet).readData(lOS);
-            if (hashProvider != null) outputStream.write(((DigestOutputStream) lOS).getMessageDigest().digest());
+            if (hashProvider != null) {
+                if (!oldPacketFormat) outputStream.write(hashProvider.getLength());
+                outputStream.write(((DigestOutputStream) lOS).getMessageDigest().digest());
+            }
         } else {
             byte[] saveArray = packet.savePayload();
-            writeInteger(outputStream, saveArray.length);
+            int pLength = saveArray.length;
+            if (hashProvider != null && !oldPacketFormat) pLength = addMostSignificantFlag(pLength);
+            writeInteger(outputStream, pLength);
             outputStream.write(saveArray);
-            if (hashProvider != null) outputStream.write(hashProvider.getDigestOf(saveArray));
+            if (hashProvider != null) {
+                if (!oldPacketFormat) outputStream.write(hashProvider.getLength());
+                outputStream.write(hashProvider.getDigestOf(saveArray));
+            }
         }
         outputStream.flush();
     }
@@ -338,10 +436,10 @@ public class PacketLoader {
      */
     public static int readInteger(InputStream inputStream) throws IOException {
         if (inputStream == null) throw new NullPointerException("inputStream is null");
-        int length = (readByteFromInputStream(inputStream) & 0xff) * 16777216;
-        length += (readByteFromInputStream(inputStream) & 0xff) * 65536;
-        length += (readByteFromInputStream(inputStream) & 0xff) * 256;
-        length += (readByteFromInputStream(inputStream) & 0xff);
+        int length = readByteIntegerFromInputStream(inputStream)* 16777216;
+        length += readByteIntegerFromInputStream(inputStream) * 65536;
+        length += readByteIntegerFromInputStream(inputStream) * 256;
+        length += readByteIntegerFromInputStream(inputStream);
         return length;
     }
 
@@ -368,6 +466,7 @@ public class PacketLoader {
 
     /**
      * Reads a byte from an {@link InputStream}.
+     * See also: {@link #readByteIntegerFromInputStream(InputStream)}.
      *
      * @param inputStream The input stream to read from.
      * @return The byte read.
@@ -381,6 +480,22 @@ public class PacketLoader {
         return (byte) toret;
     }
 
+    /**
+     * Reads a byte (In int form) from an {@link InputStream}.
+     * See also: {@link #readByteFromInputStream(InputStream)}.
+     *
+     * @param inputStream The input stream to read from.
+     * @return The byte read (As an int).
+     * @throws NullPointerException inputStream is null.
+     * @throws IOException An I/O error has occurred or end of stream has been reached.
+     */
+    public static int readByteIntegerFromInputStream(InputStream inputStream) throws IOException {
+        if (inputStream == null) throw new NullPointerException("inputStream is null");
+        int toret;
+        if ((toret = inputStream.read()) == -1) throw new IOException("inputStream end of stream");
+        return toret;
+    }
+
     /**
      * Reads in a byte array of a specified length from an {@link InputStream}.
      *
diff --git a/src/com/captainalm/lib/calmnet/packet/core/EncryptedPacket.java b/src/com/captainalm/lib/calmnet/packet/core/EncryptedPacket.java
index 903271e..0b5b1b5 100644
--- a/src/com/captainalm/lib/calmnet/packet/core/EncryptedPacket.java
+++ b/src/com/captainalm/lib/calmnet/packet/core/EncryptedPacket.java
@@ -12,7 +12,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 
-import static com.captainalm.lib.calmnet.packet.PacketLoader.readByteFromInputStream;
+import static com.captainalm.lib.calmnet.packet.PacketLoader.readByteIntegerFromInputStream;
 
 /**
  * This class provides an encrypted packet that can hold an {@link IPacket}.
@@ -358,7 +358,7 @@ public class EncryptedPacket implements IStreamedPacket, IInternalCache {
         if (size < 0) throw new IllegalArgumentException("size is less than 0");
         synchronized (slock) {
             if (size < 1) throw new IOException("inputStream end of stream");
-            int flag = readByteFromInputStream(inputStream) & 0xff;
+            int flag = readByteIntegerFromInputStream(inputStream);
 
             if (size < 5) throw new IOException("inputStream end of stream");
             int cipherLenCache = PacketLoader.readInteger(inputStream);
@@ -380,7 +380,7 @@ public class EncryptedPacket implements IStreamedPacket, IInternalCache {
             trailingArrayLengthCache = 0;
             if ((flag & 1) == 1) {
                 if (size < 9 + cipherLenCache) throw new IOException("inputStream end of stream");
-                trailingArrayLengthCache = PacketLoader.readByteFromInputStream(inputStream);
+                trailingArrayLengthCache = PacketLoader.readByteIntegerFromInputStream(inputStream);
                 if (trailingArrayLengthCache < 1) throw new PacketException("trailer length less than 1");
             }
 
diff --git a/src/com/captainalm/lib/calmnet/packet/fragment/FragmentReceiver.java b/src/com/captainalm/lib/calmnet/packet/fragment/FragmentReceiver.java
index fb1ef0e..6ef1a69 100644
--- a/src/com/captainalm/lib/calmnet/packet/fragment/FragmentReceiver.java
+++ b/src/com/captainalm/lib/calmnet/packet/fragment/FragmentReceiver.java
@@ -283,19 +283,19 @@ public final class FragmentReceiver {
     }
 
     /**
-     * Gets whether responses should be verified.
+     * Gets whether responses should be verified by sending back the payload to be verified.
      *
-     * @return Should responses be verified.
+     * @return Should responses be verified by sending back the payload.
      */
     public boolean shouldVerifyResponses() {
         return verifyResponses;
     }
 
     /**
-     * Sets whether responses should be verified.
+     * Sets whether responses should be verified by sending back the payload to be verified.
      * If set to false, {@link #setSentDataWillBeAllVerified(boolean)} will be set to false too.
      *
-     * @param state If responses should be verified.
+     * @param state If responses should be verified by sending back the payload.
      */
     public void setResponseVerification(boolean state) {
         synchronized (slock) {
@@ -305,19 +305,19 @@ public final class FragmentReceiver {
     }
 
     /**
-     * Gets whether all sent fragments are verified to be equal.
+     * Gets whether all sent fragments are expected to be verified.
      *
-     * @return If all sent fragments will be verified to be equal.
+     * @return If all sent fragments are expected to be verified.
      */
     public boolean shouldSentDataBeAllVerified() {
         return makeSureSendDataVerified;
     }
 
     /**
-     * Gets whether all sent fragments are verified to be equal.
+     * Gets whether all sent fragments are expected to be verified.
      * Requires {@link #setResponseVerification(boolean)} set to true.
      *
-     * @param state If all sent fragments will be verified to be equal.
+     * @param state If all sent fragments are expected to be verified.
      */
     public void setSentDataWillBeAllVerified(boolean state) {
         synchronized (slock) {
diff --git a/src/com/captainalm/lib/calmnet/packet/fragment/FragmentSender.java b/src/com/captainalm/lib/calmnet/packet/fragment/FragmentSender.java
index f047bb1..be9a667 100644
--- a/src/com/captainalm/lib/calmnet/packet/fragment/FragmentSender.java
+++ b/src/com/captainalm/lib/calmnet/packet/fragment/FragmentSender.java
@@ -18,7 +18,7 @@ public final class FragmentSender {
     private final HashMap<Integer, FragmentOutput> registry = new HashMap<>();
     private final Object slock = new Object();
     private final Object slockfinish = new Object();
-    private int splitSize = 496;
+    private int splitSize = 448;
     private PacketLoader packetLoader;
     private boolean verifyResponses = false;
     private boolean makeSureSendDataVerified = false;
@@ -249,7 +249,7 @@ public final class FragmentSender {
     }
 
     /**
-     * Gets whether responses should be verified.
+     * Gets whether responses should be verified by checking if they are equal.
      *
      * @return Should responses be verified.
      */
@@ -258,7 +258,7 @@ public final class FragmentSender {
     }
 
     /**
-     * Sets whether responses should be verified.
+     * Sets whether responses should be verified by checking if they are equal.
      * If set to false, {@link #setSentDataWillBeAllVerified(boolean)} will be set to false too.
      *
      * @param state If responses should be verified.
@@ -271,19 +271,19 @@ public final class FragmentSender {
     }
 
     /**
-     * Gets whether all sent fragments are verified to be equal.
+     * Gets whether all sent fragments are verified via resend checks for equality.
      *
-     * @return If all sent fragments will be verified to be equal.
+     * @return If all sent fragments will be verified via resend checks for equality.
      */
     public boolean shouldSentDataBeAllVerified() {
         return makeSureSendDataVerified;
     }
 
     /**
-     * Gets whether all sent fragments are verified to be equal.
+     * Gets whether all sent fragments are verified via resend checks for equality.
      * Requires {@link #setResponseVerification(boolean)} set to true.
      *
-     * @param state If all sent fragments will be verified to be equal.
+     * @param state If all sent fragments will be verified via resend checks for equality.
      */
     public void setSentDataWillBeAllVerified(boolean state) {
         synchronized (slock) {