diff --git a/crates/smlib/SMLIB_PREBUILT b/crates/smlib/SMLIB_PREBUILT
index b7c63d9861..d8a4e34140 100644
--- a/crates/smlib/SMLIB_PREBUILT
+++ b/crates/smlib/SMLIB_PREBUILT
@@ -1,10 +1,10 @@
 # Rust target, SHA-256 of smlib-<target>.tar.gz in the release prebuilt-<SMLIB_REV> of
 # tangency-labs/smlib. Written by scripts/fetch-smlib.sh --pin; never edited by hand.
-aarch64-apple-darwin 7fd9d91efce1734bd0c23508edc0c73cb51c628b66bb46a9bfa1dda517b97905
-aarch64-pc-windows-msvc d0eab3091b45e846270f9be9bcbce179cac81714b3b65e3af28e666496618d2c
-aarch64-unknown-linux-gnu e806ed20c2e934e5d9bf2b2399a183fa872821bab4a6535b39c5ea5f880f5aa0
-i686-pc-windows-msvc 552ad793372bf13b97948619768d15cb73339a8dd185ada680ea7f21d3b38f56
-wasm32-unknown-unknown 17709e5353b8cb9bec999481da6df679e12d0d590dec404f27e64b0b786cebff
-x86_64-apple-darwin b4af82aa01ad58005ddd2d9d9344d9673d4ed099c16e020faf87449251ea330b
-x86_64-pc-windows-msvc 64812df7d5b80e59686d88494692bac12eaab153c951a4b189dec87d79e88736
-x86_64-unknown-linux-gnu 2588040848d30ae3493777a09059f9ebe50b87f52e84d13a281f9c6a4446dd64
+aarch64-apple-darwin d88d464dc6bee7f571a3dd489f3d3d5378c70c70ab43c8076b8f8d051c0c2413
+aarch64-pc-windows-msvc 492fb4d4f89d3330f520f8284123d8bea97a44340583e74d3a3f360197f683d6
+aarch64-unknown-linux-gnu 03f9ed4de21e32301e08d54d916b06a0520c99b2c990bf445e0f624b134dcd49
+i686-pc-windows-msvc f7bb4c871b82d2a33e0a173abe446351b00d06ae877e4f0a9681b561c686d320
+wasm32-unknown-unknown b9a556940efd1ac774c630a4634e170f0d66e004021d3af43598c72bf640f2d0
+x86_64-apple-darwin cd96282ce6f6a3660c266b0b9a9ef15015b2af3328e88baca699906f50a4d5c9
+x86_64-pc-windows-msvc fd9f752fe5398eccc21c4b1fd4a48f31cf0bcad2c1408e514308a6e5ec39ef06
+x86_64-unknown-linux-gnu a778927cd0f163cfededb2c3e34e43c04612dd8f0a1770e36f2de8eabaa7cd77
diff --git a/crates/smlib/SMLIB_REV b/crates/smlib/SMLIB_REV
index ccb2feed7f..4576f5ba6e 100644
--- a/crates/smlib/SMLIB_REV
+++ b/crates/smlib/SMLIB_REV
@@ -1 +1 @@
-eaa998a30f184fefc98f7322793e3a4dc5ef68ce
+2fc375f4836c25cc87a4b2ee9082a2419f78939a
diff --git a/crates/smlib/src/ffi.rs b/crates/smlib/src/ffi.rs
index c68c200041..477b103eef 100644
--- a/crates/smlib/src/ffi.rs
+++ b/crates/smlib/src/ffi.rs
@@ -7,7 +7,7 @@
 use std::ffi::{c_char, c_void};
 
 /// `SMLIB_ABI_VERSION` this crate was written against.
-pub const ABI_VERSION: i32 = 5;
+pub const ABI_VERSION: i32 = 6;
 
 pub const OK: i32 = 0;
 pub const ERR_EXCEPTION: i32 = -1000;