diff --git a/packages/kotlin-sdk/sdk/src/androidTest/kotlin/org/dashfoundation/dashsdk/wallet/CoreWalletSetGapLimitBindingTest.kt b/packages/kotlin-sdk/sdk/src/androidTest/kotlin/org/dashfoundation/dashsdk/wallet/CoreWalletSetGapLimitBindingTest.kt
new file mode 100644
index 00000000000..455d2df71d7
--- /dev/null
+++ b/packages/kotlin-sdk/sdk/src/androidTest/kotlin/org/dashfoundation/dashsdk/wallet/CoreWalletSetGapLimitBindingTest.kt
@@ -0,0 +1,121 @@
+package org.dashfoundation.dashsdk.wallet
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import org.dashfoundation.dashsdk.errors.DashSdkError
+import org.dashfoundation.dashsdk.ffi.DashSDKException
+import org.dashfoundation.dashsdk.ffi.NativeLoader
+import org.dashfoundation.dashsdk.ffi.WalletManagerNative
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertThrows
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.junit.runner.RunWith
+
+/**
+ * Binding-level coverage for the `coreWalletSetGapLimit` JNI export — the
+ * same no-wallet discipline as [CoreTxBuilderOpReturnBindingTest]: prove the
+ * Kotlin external declaration, the generated JNI symbol, and the parameter
+ * descriptor stay in lockstep (a naming/signature mismatch surfaces here as
+ * `UnsatisfiedLinkError`, not in production), and pin each trampoline
+ * validation branch to the exception it throws. No network, no wallet, no
+ * funds.
+ *
+ * Two rejection layers are asserted apart:
+ *  - the JNI trampoline's own parameter validation throws
+ *    [DashSDKException] with RAW code 1 (the rs-sdk-ffi InvalidParameter
+ *    code) and a branch-naming message, BEFORE any FFI call;
+ *  - a well-formed call with a dead handle crosses into
+ *    `core_wallet_set_gap_limit`, whose storage miss comes back translated
+ *    into the platform-wallet code range
+ *    (>= [DashSdkError.PLATFORM_WALLET_CODE_OFFSET]) — proof the JNI
+ *    validations passed and execution reached the underlying FFI's
+ *    invalid-handle path.
+ *
+ * The branch-naming message assertions double as parameter-order pins: the
+ * three ints share one JNI descriptor slot type, so a swapped argument
+ * order in either declaration would misroute a probe into the wrong
+ * validation branch and fail the message check.
+ */
+@RunWith(AndroidJUnit4::class)
+class CoreWalletSetGapLimitBindingTest {
+
+    private fun callExpectingThrow(
+        handle: Long,
+        accountType: Int,
+        accountIndex: Int,
+        gapLimit: Int,
+    ): DashSDKException {
+        NativeLoader.ensureLoaded()
+        return assertThrows(DashSDKException::class.java) {
+            WalletManagerNative.coreWalletSetGapLimit(handle, accountType, accountIndex, gapLimit)
+        }
+    }
+
+    @Test
+    fun allSpendableAggregateIsRejectedBeforeTheFfi() {
+        // 3 = AllSpendable: it pools several accounts and has no address
+        // pool of its own, so the trampoline rejects it up front rather
+        // than letting the per-account FFI fail opaquely.
+        val e = callExpectingThrow(0L, accountType = 3, accountIndex = 0, gapLimit = 100)
+        assertEquals("JNI-side parameter rejection carries raw code 1", 1, e.code)
+        assertTrue(
+            "the rejection must name the accountType branch, got: ${e.message}",
+            e.message.orEmpty().contains("accountType"),
+        )
+    }
+
+    @Test
+    fun unknownAccountTypeIsRejectedBeforeTheFfi() {
+        // Outside the mapped range entirely — the mapping's `None` arm
+        // shares the AllSpendable rejection.
+        val e = callExpectingThrow(0L, accountType = 42, accountIndex = 0, gapLimit = 100)
+        assertEquals(1, e.code)
+        assertTrue(
+            "the rejection must name the accountType branch, got: ${e.message}",
+            e.message.orEmpty().contains("accountType"),
+        )
+    }
+
+    @Test
+    fun negativeAccountIndexIsRejectedBeforeTheFfi() {
+        val e = callExpectingThrow(0L, accountType = 0, accountIndex = -1, gapLimit = 100)
+        assertEquals(1, e.code)
+        assertTrue(
+            "the rejection must name the accountIndex branch, got: ${e.message}",
+            e.message.orEmpty().contains("accountIndex"),
+        )
+    }
+
+    @Test
+    fun nonPositiveGapLimitIsRejectedBeforeTheFfi() {
+        // 0 would freeze the address frontier and a negative jint would
+        // otherwise bit-cast to a huge u32 — both stop at the boundary.
+        for (gap in intArrayOf(0, -1)) {
+            val e = callExpectingThrow(0L, accountType = 0, accountIndex = 0, gapLimit = gap)
+            assertEquals("gapLimit $gap", 1, e.code)
+            assertTrue(
+                "the rejection must name the gapLimit branch for $gap, got: ${e.message}",
+                e.message.orEmpty().contains("gapLimit"),
+            )
+        }
+    }
+
+    @Test
+    fun concreteAccountTypesReachTheFfiInvalidHandlePath() {
+        // 0 BIP44, 1 BIP32, 2 CoinJoin — every concrete arm of the
+        // trampoline's account-type mapping must pass validation and cross
+        // into `core_wallet_set_gap_limit`, where handle 0 can never be a
+        // live core wallet. The FFI's miss comes back translated into the
+        // platform-wallet code range — NOT the trampoline's raw code 1 —
+        // which proves the call left the JNI layer and the concrete arms
+        // are wired through.
+        for (accountType in intArrayOf(0, 1, 2)) {
+            val e = callExpectingThrow(0L, accountType, accountIndex = 0, gapLimit = 100)
+            assertTrue(
+                "type $accountType must fail inside the FFI (translated code >= " +
+                    "${DashSdkError.PLATFORM_WALLET_CODE_OFFSET}), got ${e.code}: ${e.message}",
+                e.code >= DashSdkError.PLATFORM_WALLET_CODE_OFFSET,
+            )
+        }
+    }
+}
diff --git a/packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/ffi/WalletManagerNative.kt b/packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/ffi/WalletManagerNative.kt
index 40bdef869c3..d0c4e9f2f53 100644
--- a/packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/ffi/WalletManagerNative.kt
+++ b/packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/ffi/WalletManagerNative.kt
@@ -128,6 +128,23 @@ internal object WalletManagerNative {
     /** Balance as `long[4]` = {confirmed, unconfirmed, immature, locked}. */
     external fun walletGetBalance(walletHandle: Long): LongArray
 
+    /**
+     * Widen an account's address-pool gap limit, generating the addresses
+     * the wider limit now requires (capped Rust-side at MAX_GAP_LIMIT =
+     * 1000). The compact-filter scan watches `last used index + gap`, so
+     * this is the host's lever for wallets whose usage frontier advanced
+     * OUTSIDE the SDK's view (another client on the same seed spending
+     * past the default window). `accountType`: 0 BIP44, 1 BIP32,
+     * 2 CoinJoin — AllSpendable (3) is rejected, gap limits are
+     * per-account.
+     */
+    external fun coreWalletSetGapLimit(
+        walletHandle: Long,
+        accountType: Int,
+        accountIndex: Int,
+        gapLimit: Int,
+    )
+
     // ── Core transaction builder (1:1 over `core_wallet_tx_builder_*`) ─
     //
     // Each step is a thin extern (one export = one FFI call, per
diff --git a/packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/wallet/ManagedCoreWallet.kt b/packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/wallet/ManagedCoreWallet.kt
index dbed938ea3e..37aca33c542 100644
--- a/packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/wallet/ManagedCoreWallet.kt
+++ b/packages/kotlin-sdk/sdk/src/main/kotlin/org/dashfoundation/dashsdk/wallet/ManagedCoreWallet.kt
@@ -27,6 +27,27 @@ class ManagedCoreWallet internal constructor(handle: Long) : AutoCloseable {
             check(it != 0L) { "ManagedCoreWallet has been closed" }
         }
 
+    /**
+     * Widen [accountType]/[accountIndex]'s address-pool gap limit,
+     * deriving the addresses the wider limit requires (Rust caps at
+     * 1000). Use when the seed's usage frontier moved outside the SDK's
+     * watched window — e.g. a migrated wallet whose other client (dashj)
+     * kept spending — then re-scan so the newly watched scripts match
+     * their history.
+     */
+    fun setGapLimit(
+        accountType: CoreTransactionBuilder.AccountType,
+        accountIndex: Int,
+        gapLimit: Int,
+    ): Unit = mapNativeErrors {
+        WalletManagerNative.coreWalletSetGapLimit(
+            handle,
+            accountType.ffiValue,
+            accountIndex,
+            gapLimit,
+        )
+    }
+
     /** Consume and broadcast a finalized transaction. */
     fun broadcastTransaction(tx: FinalizedCoreTransaction): String =
         WalletManagerNative.coreWalletBroadcastSignedTransaction(
diff --git a/packages/rs-unified-sdk-jni/src/wallet_manager.rs b/packages/rs-unified-sdk-jni/src/wallet_manager.rs
index 1cc5801db3e..0fb4ac022a6 100644
--- a/packages/rs-unified-sdk-jni/src/wallet_manager.rs
+++ b/packages/rs-unified-sdk-jni/src/wallet_manager.rs
@@ -623,6 +623,59 @@ pub extern "system" fn Java_org_dashfoundation_dashsdk_ffi_WalletManagerNative_w
     })
 }
 
+/// `core_wallet_set_gap_limit` — widen an account's address-pool gap
+/// limit, generating the addresses the wider limit now requires (capped
+/// Rust-side at `MAX_GAP_LIMIT`). The window a compact-filter scan watches
+/// is `last used index + gap`, so this is the host's lever for wallets
+/// whose usage frontier moved OUTSIDE the SDK's view (another client on
+/// the same seed — dashj during the migration — spending past the default
+/// window; observed in the field as change addresses the SDK refused to
+/// recognise). `account_type`: 0 BIP44, 1 BIP32, 2 CoinJoin
+/// (3 AllSpendable is rejected — gap limits are per-account).
+#[no_mangle]
+pub extern "system" fn Java_org_dashfoundation_dashsdk_ffi_WalletManagerNative_coreWalletSetGapLimit(
+    mut env: JNIEnv,
+    _class: JClass,
+    wallet_handle: jlong,
+    account_type: jni::sys::jint,
+    account_index: jni::sys::jint,
+    gap_limit: jni::sys::jint,
+) {
+    guard(&mut env, (), |env| {
+        // A gap limit belongs to ONE account's address pools; the
+        // AllSpendable aggregate (3) has no pool of its own, so reject it
+        // here rather than letting the per-account FFI fail opaquely.
+        let account_type = match core_account_type(account_type) {
+            Some(platform_wallet_ffi::CoreAccountTypeFFI::AllSpendable) | None => {
+                throw_sdk_exception(
+                    env,
+                    1,
+                    "accountType must be a concrete account (0=BIP44, 1=BIP32, 2=CoinJoin)",
+                );
+                return;
+            }
+            Some(concrete) => concrete,
+        };
+        if account_index < 0 {
+            throw_sdk_exception(env, 1, "accountIndex must be non-negative");
+            return;
+        }
+        if gap_limit <= 0 {
+            throw_sdk_exception(env, 1, "gapLimit must be positive");
+            return;
+        }
+        let result = unsafe {
+            platform_wallet_ffi::core_wallet_set_gap_limit(
+                wallet_handle as Handle,
+                account_type,
+                account_index as u32,
+                gap_limit as u32,
+            )
+        };
+        let _ = take_pwffi_error(env, result);
+    })
+}
+
 // ── Core transaction builder (1:1 over `core_wallet_tx_builder_*`) ─────
 //
 // The base refactor replaced the one-shot `core_wallet_send_to_addresses`