diff --git a/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeData.java b/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeData.java
index 44eb1c3c..1ebc6525 100644
--- a/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeData.java
+++ b/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeData.java
@@ -37,6 +37,7 @@ import org.geysermc.floodgate.util.LinkedPlayer;
  * server. Note that at the time I'm writing this that the HandshakeData is created after requesting
  * the player link. So the link is present here, if applicable.
  */
+@Deprecated
 public interface HandshakeData {
     /**
      * Returns the Channel holding the connection between the client and the server.
diff --git a/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandler.java b/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandler.java
index 2aca5498..8ce06253 100644
--- a/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandler.java
+++ b/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandler.java
@@ -34,6 +34,7 @@ package org.geysermc.floodgate.api.handshake;
  * HandshakeData#isFloodgatePlayer()} will be false and Floodgate related methods will return null
  * for Java players
  */
+@Deprecated
 @FunctionalInterface
 public interface HandshakeHandler {
     /**
diff --git a/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandlers.java b/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandlers.java
index ef19b545..088ac9af 100644
--- a/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandlers.java
+++ b/api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandlers.java
@@ -25,6 +25,13 @@
 
 package org.geysermc.floodgate.api.handshake;
 
+/**
+ * @deprecated This system has been deprecated and will not be available in the new API that will be
+ * introduced when Geyser will include Floodgate (and thus will have some common base API).
+ * <br>
+ * It might be replaced with an event (probably internal), but that isn't certain yet.
+ */
+@Deprecated
 public interface HandshakeHandlers {
     /**
      * Register a custom handshake handler. This can be used to check and edit the player during the
diff --git a/api/src/main/java/org/geysermc/floodgate/api/player/FloodgatePlayer.java b/api/src/main/java/org/geysermc/floodgate/api/player/FloodgatePlayer.java
index c69578c5..6205da0d 100644
--- a/api/src/main/java/org/geysermc/floodgate/api/player/FloodgatePlayer.java
+++ b/api/src/main/java/org/geysermc/floodgate/api/player/FloodgatePlayer.java
@@ -143,20 +143,28 @@ public interface FloodgatePlayer {
         return FloodgateApi.getInstance().transferPlayer(getCorrectUniqueId(), address, port);
     }
 
+    @Deprecated
     boolean hasProperty(PropertyKey key);
 
+    @Deprecated
     boolean hasProperty(String key);
 
+    @Deprecated
     <T> T getProperty(PropertyKey key);
 
+    @Deprecated
     <T> T getProperty(String key);
 
+    @Deprecated
     <T> T removeProperty(PropertyKey key);
 
+    @Deprecated
     <T> T removeProperty(String key);
 
+    @Deprecated
     <T> T addProperty(PropertyKey key, Object value);
 
+    @Deprecated
     <T> T addProperty(String key, Object value);
 
     /**
diff --git a/api/src/main/java/org/geysermc/floodgate/api/player/PropertyKey.java b/api/src/main/java/org/geysermc/floodgate/api/player/PropertyKey.java
index 04e1d4d0..62bebaf8 100644
--- a/api/src/main/java/org/geysermc/floodgate/api/player/PropertyKey.java
+++ b/api/src/main/java/org/geysermc/floodgate/api/player/PropertyKey.java
@@ -28,6 +28,7 @@ package org.geysermc.floodgate.api.player;
 import lombok.Getter;
 
 @Getter
+@Deprecated
 public class PropertyKey {
     /**
      * Socket Address returns the InetSocketAddress of the Bedrock player