diff --git a/solana/programs/stable-swapper/src/constants.rs b/solana/programs/stable-swapper/src/constants.rs
index cc9397b..bb5262e 100644
--- a/solana/programs/stable-swapper/src/constants.rs
+++ b/solana/programs/stable-swapper/src/constants.rs
@@ -27,3 +27,6 @@ pub const TOKEN_VAULT_SEED: &[u8] = b"token_vault";
 
 /// Seed for vault token account PDA
 pub const VAULT_TOKEN_ACCOUNT_SEED: &[u8] = b"vault_token_account";
+
+/// Seed for address whitelist PDA
+pub const ADDRESS_WHITELIST_SEED: &[u8] = b"address_whitelist";
diff --git a/solana/programs/stable-swapper/src/lib.rs b/solana/programs/stable-swapper/src/lib.rs
index 2f08e5c..e1bcd4c 100644
--- a/solana/programs/stable-swapper/src/lib.rs
+++ b/solana/programs/stable-swapper/src/lib.rs
@@ -14,10 +14,6 @@ use utils::*;
 
 declare_id!("pqgqKahpG1y2wsgxFhzaAnkV1cL9vk8MSg9qm4q646F");
 
-// NOTE: The previously deployed whitelist PDA (seeded b"address_whitelist") is orphaned
-// on devnet/mainnet after whitelist removal. Its rent is intentionally forfeited; adding a
-// close_whitelist instruction is not worth the complexity for the small amount involved.
-
 #[program]
 pub mod stable_swapper {
     use super::*;
@@ -173,6 +169,11 @@ pub mod stable_swapper {
         require!(amount_in > 0, LiquidityError::InvalidAmount);
         require!(min_amount_out > 0, LiquidityError::InvalidAmount);
 
+        // Whitelist enforcement is permanently deprecated. `whitelist` stays in this
+        // instruction's account list (see the field below) purely so already-encoded
+        // callers/indexers built against the pre-deprecation `swap` signature keep working;
+        // nothing reads or writes it anymore.
+
         // Check that neither token is disabled
         require!(
             !ctx.accounts.in_vault.disabled,
@@ -907,6 +908,17 @@ pub struct Swap<'info> {
     #[account(mut)]
     pub user: Signer<'info>,
 
+    /// Deprecated whitelist PDA. Kept only so the account list matches the
+    /// pre-deprecation `swap` signature that existing callers/indexers already encode;
+    /// its data is never read. On mainnet this resolves to the orphaned whitelist account
+    /// left behind by the original removal; on fresh deployments it need not exist at all.
+    /// CHECK: seeds-verified PDA address only; deliberately not deserialized.
+    #[account(
+        seeds = [ADDRESS_WHITELIST_SEED],
+        bump
+    )]
+    pub whitelist: UncheckedAccount<'info>,
+
     pub token_program: Program<'info, Token>,
     pub associated_token_program: Program<'info, AssociatedToken>,
     pub system_program: Program<'info, System>,