diff --git a/bootstrap/spigot/pom.xml b/bootstrap/spigot/pom.xml
index 5d17d2619..5aa2c59cf 100644
--- a/bootstrap/spigot/pom.xml
+++ b/bootstrap/spigot/pom.xml
@@ -11,6 +11,10 @@
     <artifactId>bootstrap-spigot</artifactId>
 
     <repositories>
+        <repository>
+            <id>papermc</id>
+            <url>https://papermc.io/repo/repository/maven-public/</url>
+        </repository>
         <repository>
             <id>viaversion-repo</id>
             <url>https://repo.viaversion.com</url>
@@ -25,9 +29,9 @@
             <scope>compile</scope>
         </dependency>
         <dependency>
-            <groupId>org.spigotmc</groupId>
-            <artifactId>spigot-api</artifactId>
-            <version>1.15.2-R0.1-SNAPSHOT</version>
+            <groupId>io.papermc.paper</groupId>
+            <artifactId>paper-api</artifactId>
+            <version>1.18.1-R0.1-SNAPSHOT</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
diff --git a/bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserSpigotPlugin.java b/bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserSpigotPlugin.java
index 12a27190d..6b6344bd8 100644
--- a/bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserSpigotPlugin.java
+++ b/bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserSpigotPlugin.java
@@ -168,8 +168,7 @@ public class GeyserSpigotPlugin extends JavaPlugin implements GeyserBootstrap {
                 // Ensure that we have the latest 4.0.0 changes and not an older ViaVersion version
                 Class.forName("com.viaversion.viaversion.api.ViaManager");
             } catch (ClassNotFoundException e) {
-                geyserLogger.warning(GeyserLocale.getLocaleStringLog("geyser.bootstrap.viaversion.too_old",
-                        "https://ci.viaversion.com/job/ViaVersion/"));
+                GeyserSpigotVersionChecker.sendOutdatedViaVersionMessage(geyserLogger);
                 isViaVersion = false;
                 if (this.geyserConfig.isDebugMode()) {
                     e.printStackTrace();
@@ -242,6 +241,9 @@ public class GeyserSpigotPlugin extends JavaPlugin implements GeyserBootstrap {
         }
 
         this.getCommand("geyser").setExecutor(new GeyserSpigotCommandExecutor(geyser));
+
+        // Check to ensure the current setup can support the protocol version Geyser uses
+        GeyserSpigotVersionChecker.checkForSupportedProtocol(geyserLogger, isViaVersion);
     }
 
     @Override
diff --git a/bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserSpigotVersionChecker.java b/bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserSpigotVersionChecker.java
new file mode 100644
index 000000000..749323a1f
--- /dev/null
+++ b/bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserSpigotVersionChecker.java
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Geyser
+ */
+
+package org.geysermc.geyser.platform.spigot;
+
+import com.viaversion.viaversion.api.Via;
+import org.bukkit.Bukkit;
+import org.bukkit.UnsafeValues;
+import org.geysermc.geyser.GeyserLogger;
+import org.geysermc.geyser.network.MinecraftProtocol;
+import org.geysermc.geyser.text.GeyserLocale;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+
+public final class GeyserSpigotVersionChecker {
+    private static final String VIAVERSION_DOWNLOAD_URL = "https://ci.viaversion.com/job/ViaVersion/";
+
+    public static void checkForSupportedProtocol(GeyserLogger logger, boolean viaversion) {
+        if (viaversion) {
+            checkViaVersionSupportedVersions(logger);
+            return;
+        }
+
+        try {
+            // This method is only present on later versions of Paper
+            UnsafeValues.class.getMethod("getProtocolVersion");
+            if (Bukkit.getUnsafe().getProtocolVersion() != MinecraftProtocol.getJavaProtocolVersion()) {
+                sendOutdatedMessage(logger);
+            }
+            return;
+        } catch (NoSuchMethodException ignored) {
+        }
+
+        // Otherwise, we can just try to find the SharedConstants class
+        // It isn't present in all server versions, but if we can't find it, then we're probably not in the latest version
+        Class<?> sharedConstants;
+        try {
+            sharedConstants = Class.forName("net.minecraft.SharedConstants");
+        } catch (ClassNotFoundException e) {
+            // We're using pre-1.17
+            String prefix = Bukkit.getServer().getClass().getPackage().getName().replace("org.bukkit.craftbukkit", "net.minecraft.server");
+            try {
+                sharedConstants = Class.forName(prefix + ".SharedConstants");
+            } catch (ClassNotFoundException e2) {
+                sendOutdatedMessage(logger);
+                return;
+            }
+        }
+        for (Method method : sharedConstants.getMethods()) {
+            if (method.getReturnType() == int.class && Modifier.isStatic(method.getModifiers())) {
+                int protocolVersion;
+                try {
+                    protocolVersion = (int) method.invoke(null);
+                } catch (IllegalAccessException | InvocationTargetException e) {
+                    logger.warning("Could not determine server version! This is safe to ignore, but please report to the developers: " + e.getMessage());
+                    if (logger.isDebug()) {
+                        e.printStackTrace();
+                    }
+                    return;
+                }
+                if (protocolVersion != MinecraftProtocol.getJavaProtocolVersion()) {
+                    sendOutdatedMessage(logger);
+                }
+                return;
+            }
+        }
+        sendOutdatedMessage(logger);
+    }
+
+    private static void checkViaVersionSupportedVersions(GeyserLogger logger) {
+        // Run after ViaVersion has obtained the server protocol version
+        Via.getPlatform().runSync(() -> {
+            if (Via.getAPI().getSupportedVersions().contains(MinecraftProtocol.getJavaProtocolVersion())) {
+                // Via supports this protocol version; we will be able to connect.
+                return;
+            }
+            if (Via.getAPI().getFullSupportedVersions().contains(MinecraftProtocol.getJavaProtocolVersion())) {
+                // ViaVersion supports our protocol, but the user has blocked them from connecting.
+                logger.warning(GeyserLocale.getLocaleStringLog("geyser.bootstrap.viaversion.blocked", MinecraftProtocol.getAllSupportedJavaVersions()));
+                return;
+            }
+            // Else, presumably, ViaVersion is not updated.
+            sendOutdatedViaVersionMessage(logger);
+        });
+    }
+
+    public static void sendOutdatedViaVersionMessage(GeyserLogger logger) {
+        logger.warning(GeyserLocale.getLocaleStringLog("geyser.bootstrap.viaversion.too_old",
+                VIAVERSION_DOWNLOAD_URL));
+    }
+
+    private static void sendOutdatedMessage(GeyserLogger logger) {
+        logger.warning(GeyserLocale.getLocaleStringLog("geyser.bootstrap.no_supported_protocol", MinecraftProtocol.getAllSupportedJavaVersions(), VIAVERSION_DOWNLOAD_URL));
+    }
+
+    private GeyserSpigotVersionChecker() {
+    }
+}