diff --git a/sdgb-api/src/title/encryption/mod.rs b/sdgb-api/src/title/encryption/mod.rs
index fc33094..b0ee0ed 100644
--- a/sdgb-api/src/title/encryption/mod.rs
+++ b/sdgb-api/src/title/encryption/mod.rs
@@ -9,36 +9,7 @@ use flate2::write::{ZlibDecoder, ZlibEncoder};
 use spdlog::debug;
 
 use crate::error::ApiError;
-use crate::title::{MaiVersion, MaiVersionExt, Sdgb1_40, Sdgb1_50};
-
-impl MaiVersionExt for Sdgb1_40 {
-    fn decode(mut data: impl AsMut<[u8]>) -> Result<Vec<u8>, ApiError> {
-        let mut decompressed = decompress(data.as_mut());
-        if decompressed.is_empty() {
-            return Err(ApiError::EmptyResponse);
-        }
-
-        let orig_len = decompressed.len();
-
-        let remain = 16 - decompressed.len() % 16;
-
-        if
-        // weird but nessacary for Rust Pkcs7
-        remain != 16 {
-            decompressed.resize(remain + orig_len, remain as _);
-        }
-
-        let unpad_size = decrypt(&mut decompressed, Self::AES_KEY, Self::AES_IV)?.len();
-        decompressed.truncate(unpad_size);
-        Ok(decompressed)
-    }
-
-    fn encode(data: impl AsRef<[u8]>) -> Result<Vec<u8>, ApiError> {
-        let enc = encrypt(data, Self::AES_KEY, Self::AES_IV)?;
-        let compressed = compress(enc)?;
-        Ok(compressed)
-    }
-}
+use crate::title::{MaiVersion, MaiVersionExt, Sdgb1_50};
 
 impl MaiVersionExt for Sdgb1_50 {
     fn decode(mut data: impl AsMut<[u8]>) -> Result<Vec<u8>, ApiError> {
@@ -110,21 +81,6 @@ mod _tests {
 
     use crate::title::{Sdgb1_50, encryption::*};
 
-    #[test]
-    fn test_sdgb_140_dec_enc() -> Result<(), ApiError> {
-        let data = [
-            120_u8, 156, 171, 77, 91, 233, 184, 108, 2, 71, 125, 142, 118, 135, 112, 181, 85, 217,
-            239, 243, 159, 153, 248, 98, 159, 185, 63, 43, 173, 106, 221, 115, 104, 105, 221, 107,
-            0, 241, 176, 16, 37,
-        ];
-
-        let dec = Sdgb1_40::decode(data)?;
-        assert_eq!(dec, br#"{"result":"Pong"}"#);
-        let enc = Sdgb1_40::encode(dec)?;
-        assert_eq!(enc, data);
-        Ok(())
-    }
-
     #[test]
     fn test_sdgb_150_dec_enc() -> Result<(), ApiError> {
         let data = [
diff --git a/sdgb-api/src/title/mod.rs b/sdgb-api/src/title/mod.rs
index e0074d0..07180ff 100644
--- a/sdgb-api/src/title/mod.rs
+++ b/sdgb-api/src/title/mod.rs
@@ -117,16 +117,8 @@ pub trait MaiVersionExt: MaiVersion {
     }
 }
 
-pub struct Sdgb1_40;
 pub struct Sdgb1_50;
 
-impl MaiVersion for Sdgb1_40 {
-    const AES_KEY: &[u8; 32] = b"n7bx6:@Fg_:2;5E89Phy7AyIcpxEQ:R@";
-    const AES_IV: &[u8; 16] = b";;KjR1C3hgB1ovXa";
-    const OBFUSECATE_SUFFIX: &str = "MaimaiChnBEs2D5vW";
-
-    const VERSION: &str = "1.40";
-}
 impl MaiVersion for Sdgb1_50 {
     const AES_KEY: &[u8; 32] = b"a>32bVP7v<63BVLkY[xM>daZ1s9MBP<R";
     const AES_IV: &[u8; 16] = b"d6xHIKq]1J]Dt^ue";
diff --git a/sdgb-cli/src/main.rs b/sdgb-cli/src/main.rs
index c9b0857..97eba97 100644
--- a/sdgb-cli/src/main.rs
+++ b/sdgb-cli/src/main.rs
@@ -12,7 +12,7 @@ use sdgb_api::{
     auth_lite::{SDGB, SDHJ, delivery_raw},
     helper::MUSIC_DB,
     title::{
-        MaiVersionExt, Sdgb1_40, Sdgb1_50,
+        MaiVersionExt, Sdgb1_50,
         methods::APIMethod,
         model::{
             DataVersion, DxCalculatedEntries, DxRatingNet, GetUserDataApi, GetUserDataApiResp,
@@ -167,14 +167,6 @@ async fn main() -> Result<(), Box<dyn snafu::Error>> {
             human_readable_display(preview, human_readable)?;
         }
         commands::Commands::Ping => {
-            let decoded: PingResp = Sdgb1_40::request(
-                &client,
-                APIMethod::Ping,
-                "",
-                Ping {}, // note: must not be `Ping`, or serde_json serializes to nothing
-            )
-            .await?;
-            info!("sdgb 1.40 resp: {decoded}");
             let decoded: PingResp =
                 Sdgb1_50::request(&client, APIMethod::Ping, "", Ping {}).await?;
             info!("sdgb 1.50 resp: {decoded}");