diff --git a/src/main/java/vip/fubuki/playersync/config/JdbcConfig.java b/src/main/java/vip/fubuki/playersync/config/JdbcConfig.java
index d51ce1f..7852560 100644
--- a/src/main/java/vip/fubuki/playersync/config/JdbcConfig.java
+++ b/src/main/java/vip/fubuki/playersync/config/JdbcConfig.java
@@ -21,6 +21,7 @@ public class JdbcConfig {
     public static ForgeConfigSpec.BooleanValue IS_CHAT_SERVER;
     public static ForgeConfigSpec.ConfigValue<String> CHAT_SERVER_IP;
     public static ForgeConfigSpec.IntValue CHAT_SERVER_PORT;
+    public static ForgeConfigSpec.BooleanValue USE_LEGACY_SERIALIZATION;
 
     public static ForgeConfigSpec.ConfigValue<Integer> SERVER_ID;
 
@@ -40,8 +41,13 @@ public class JdbcConfig {
         IS_CHAT_SERVER = COMMON_BUILDER.comment("Whether recieve messages from other servers as host").define("IsChatServer",false);
         CHAT_SERVER_IP = COMMON_BUILDER.define("ChatServerIP","127.0.0.1");
         CHAT_SERVER_PORT = COMMON_BUILDER.defineInRange("ChatServerPort",7900,0,65535);
+        USE_LEGACY_SERIALIZATION = COMMON_BUILDER.comment(
+                "Use the old (pre-Base64) serialization format for writing data to the database.",
+                "Set to true ONLY if you have older mod versions reading the same database.",
+                "This only affects writing data, the mod can read both Base64 and pre-Base64 serialization.",
+                "New installations should leave this as 'false'."
+            ).define("use_legacy_serialization", false);
         COMMON_BUILDER.pop();
         COMMON_CONFIG = COMMON_BUILDER.build();
     }
 }
-
diff --git a/src/main/java/vip/fubuki/playersync/sync/VanillaSync.java b/src/main/java/vip/fubuki/playersync/sync/VanillaSync.java
index aa296af..0375cc0 100644
--- a/src/main/java/vip/fubuki/playersync/sync/VanillaSync.java
+++ b/src/main/java/vip/fubuki/playersync/sync/VanillaSync.java
@@ -188,6 +188,12 @@ public class VanillaSync {
         return ItemStack.of(compoundTag);
     }
 
+    /**
+     * Deserializes a string from the database back into an NBT string.
+     * Handles both the new Base64 format (prefixed with "B64:") and the old custom format.
+     * @param encoded The string retrieved from the database.
+     * @return The deserialized NBT string.
+     */
     public static String deserializeString(String encoded) {
         if (encoded.startsWith("B64:")) {
             String base64 = encoded.substring(4);
@@ -206,7 +212,24 @@ public class VanillaSync {
                 .replace("~", "'");
     }
 
+    /**
+     * Serializes an NBT string for database storage.
+     * Uses Base64 encoding by default (prefixed with "B64:").
+     * If USE_LEGACY_SERIALIZATION config is true, uses the old custom replacement format.
+     * @param object The NBT string to serialize.
+     * @return The serialized string.
+     */
     public static String serialize(String object) {
+        // Check the config option for backwards compatibility during writing
+        if (JdbcConfig.USE_LEGACY_SERIALIZATION.get()) {
+            // Use old custom replacement logic
+            return objeåct.replace(",", "|")
+                         .replace("\"", "^")
+                         .replace("{", "<")
+                         .replace("}", ">")
+                         .replace("'", "~");
+        }
+
         // Base64 encode with a "B64:" marker for new data
         return "B64:" + Base64.getEncoder().encodeToString(object.getBytes(StandardCharsets.UTF_8));
     }