diff --git a/dune-project b/dune-project
index 6554bf67..c423bd2b 100644
--- a/dune-project
+++ b/dune-project
@@ -52,7 +52,7 @@
   ocaml_intrinsics
   (prelude (>= 0.3))
   sedlex
-  (smtml (>= 0.2.3))
+  (smtml (>= 0.3.1))
   uutf
   xmlm
   (processor (>= 0.2))
diff --git a/owi.opam b/owi.opam
index 780cbad0..4196a967 100644
--- a/owi.opam
+++ b/owi.opam
@@ -29,7 +29,7 @@ depends: [
   "ocaml_intrinsics"
   "prelude" {>= "0.3"}
   "sedlex"
-  "smtml" {>= "0.2.3"}
+  "smtml" {>= "0.3.1"}
   "uutf"
   "xmlm"
   "processor" {>= "0.2"}
diff --git a/src/concolic/concolic_wasm_ffi.ml b/src/concolic/concolic_wasm_ffi.ml
index 17b44bf5..289aaaf8 100644
--- a/src/concolic/concolic_wasm_ffi.ml
+++ b/src/concolic/concolic_wasm_ffi.ml
@@ -26,7 +26,7 @@ module M :
           | Some (Num (I32 n)) -> n
           | _ -> assert false
         in
-        (I32 n, Value.pair n (Expr.mk_symbol sym)) )
+        (I32 n, Value.pair n (Expr.symbol sym)) )
 
   let symbol_i8 () : Value.int32 Choice.t =
     Choice.with_new_symbol (Ty_bitv 32) (fun sym forced_value ->
@@ -37,7 +37,7 @@ module M :
           | _ -> assert false
         in
         let sym_expr =
-          Expr.make (Cvtop (Ty_bitv 32, Zero_extend 24, Expr.mk_symbol sym))
+          Expr.make (Cvtop (Ty_bitv 32, Zero_extend 24, Expr.symbol sym))
         in
         (I32 n, Value.pair n sym_expr) )
 
@@ -50,7 +50,7 @@ module M :
           | _ -> assert false
         in
         let sym_expr =
-          Expr.make (Cvtop (Ty_bitv 32, Zero_extend 24, Expr.mk_symbol sym))
+          Expr.make (Cvtop (Ty_bitv 32, Zero_extend 24, Expr.symbol sym))
         in
         (I32 n, Value.pair n sym_expr) )
 
@@ -62,7 +62,7 @@ module M :
           | Some (Num (I64 n)) -> n
           | _ -> assert false
         in
-        (I64 n, Value.pair n (Expr.mk_symbol sym)) )
+        (I64 n, Value.pair n (Expr.symbol sym)) )
 
   let symbol_f32 () : Value.float32 Choice.t =
     Choice.with_new_symbol (Ty_fp 32) (fun sym forced_value ->
@@ -73,7 +73,7 @@ module M :
           | _ -> assert false
         in
         let n = Float32.of_bits n in
-        (F32 n, Value.pair n (Expr.mk_symbol sym)) )
+        (F32 n, Value.pair n (Expr.symbol sym)) )
 
   let symbol_f64 () : Value.float64 Choice.t =
     Choice.with_new_symbol (Ty_fp 64) (fun sym forced_value ->
@@ -84,7 +84,7 @@ module M :
           | _ -> assert false
         in
         let n = Float64.of_bits n in
-        (F64 n, Value.pair n (Expr.mk_symbol sym)) )
+        (F64 n, Value.pair n (Expr.symbol sym)) )
 
   let assume_i32 (i : Value.int32) : unit Choice.t =
     let c = Value.I32.to_bool i in
diff --git a/src/symbolic/symbolic_choice.ml b/src/symbolic/symbolic_choice.ml
index 8c489dbb..55e81ccf 100644
--- a/src/symbolic/symbolic_choice.ml
+++ b/src/symbolic/symbolic_choice.ml
@@ -420,7 +420,7 @@ module Make (Thread : Thread.S) = struct
       let sym_name = Fmt.str "choice_i32_%i" num_symbols in
       let sym_type = Smtml.Ty.Ty_bitv 32 in
       let sym = Smtml.Symbol.make sym_type sym_name in
-      let assign = Smtml.Expr.(relop Ty_bool Eq (mk_symbol sym) e) in
+      let assign = Smtml.Expr.(relop Ty_bool Eq (symbol sym) e) in
       (Some assign, sym)
 
   let select_i32 (i : Symbolic_value.int32) =
@@ -440,7 +440,7 @@ module Make (Thread : Thread.S) = struct
           | Smtml.Value.Num (I32 i) -> i
           | _ -> Fmt.failwith "Unreachable: found symbol must be a value"
         in
-        let s = Smtml.Expr.mk_symbol symbol in
+        let s = Smtml.Expr.symbol symbol in
         let this_value_cond =
           let open Smtml.Expr in
           Bitv.I32.(s = v i)
diff --git a/src/symbolic/symbolic_memory_concretizing.ml b/src/symbolic/symbolic_memory_concretizing.ml
index 16fcd672..47578ce5 100644
--- a/src/symbolic/symbolic_memory_concretizing.ml
+++ b/src/symbolic/symbolic_memory_concretizing.ml
@@ -1,6 +1,4 @@
 module Backend = struct
-  open Smtml
-
   type address = Int32.t
 
   type t =
@@ -21,7 +19,7 @@ module Backend = struct
 
   let address a =
     let open Symbolic_choice_without_memory in
-    match Expr.view a with
+    match Smtml.Expr.view a with
     | Val (Num (I32 i)) -> return i
     | Ptr { base; offset } ->
       select_i32 Symbolic_value.(I32.add (const_i32 base) offset)
@@ -33,21 +31,22 @@ module Backend = struct
     try Hashtbl.find data a
     with Not_found -> (
       match parent with
-      | None -> Expr.value (Num (I8 0))
+      | None -> Smtml.Expr.value (Num (I8 0))
       | Some parent -> load_byte parent a )
 
   (* TODO: don't rebuild so many values it generates unecessary hc lookups *)
   let merge_extracts (e1, h, m1) (e2, m2, l) =
-    let ty = Expr.ty e1 in
-    if m1 = m2 && Expr.equal e1 e2 then
-      if h - l = Ty.size ty then e1 else Expr.make (Extract (e1, h, l))
+    let ty = Smtml.Expr.ty e1 in
+    if m1 = m2 && Smtml.Expr.equal e1 e2 then
+      if h - l = Smtml.Ty.size ty then e1
+      else Smtml.Expr.make (Extract (e1, h, l))
     else
-      Expr.(
+      Smtml.Expr.(
         make (Concat (make (Extract (e1, h, m1)), make (Extract (e2, m2, l)))) )
 
   let concat ~msb ~lsb offset =
     assert (offset > 0 && offset <= 8);
-    match (Expr.view msb, Expr.view lsb) with
+    match (Smtml.Expr.view msb, Smtml.Expr.view lsb) with
     | Val (Num (I8 i1)), Val (Num (I8 i2)) ->
       Symbolic_value.const_i32 Int32.(logor (shl (of_int i1) 8l) (of_int i2))
     | Val (Num (I8 i1)), Val (Num (I32 i2)) ->
@@ -65,8 +64,8 @@ module Backend = struct
     | Extract (e1, h, m1), Extract (e2, m2, l) ->
       merge_extracts (e1, h, m1) (e2, m2, l)
     | Extract (e1, h, m1), Concat ({ node = Extract (e2, m2, l); _ }, e3) ->
-      Expr.(make (Concat (merge_extracts (e1, h, m1) (e2, m2, l), e3)))
-    | _ -> Expr.make (Concat (msb, lsb))
+      Smtml.Expr.(make (Concat (merge_extracts (e1, h, m1) (e2, m2, l), e3)))
+    | _ -> Smtml.Expr.make (Concat (msb, lsb))
 
   let loadn m a n =
     let rec loop addr size i acc =
@@ -80,21 +79,21 @@ module Backend = struct
     loop a n 1 v0
 
   let extract v pos =
-    match Expr.view v with
+    match Smtml.Expr.view v with
     | Val (Num (I8 _)) -> v
     | Val (Num (I32 i)) ->
       let i' = Int32.(to_int @@ logand 0xffl @@ shr_s i @@ of_int (pos * 8)) in
-      Expr.value (Num (I8 i'))
+      Smtml.Expr.value (Num (I8 i'))
     | Val (Num (I64 i)) ->
       let i' = Int64.(to_int @@ logand 0xffL @@ shr_s i @@ of_int (pos * 8)) in
-      Expr.value (Num (I8 i'))
+      Smtml.Expr.value (Num (I8 i'))
     | Cvtop
         (_, Zero_extend 24, ({ node = Symbol { ty = Ty_bitv 8; _ }; _ } as sym))
     | Cvtop
         (_, Sign_extend 24, ({ node = Symbol { ty = Ty_bitv 8; _ }; _ } as sym))
       ->
       sym
-    | _ -> Expr.make (Extract (v, pos + 1, pos))
+    | _ -> Smtml.Expr.make (Extract (v, pos + 1, pos))
 
   let storen m a v n =
     for i = 0 to n - 1 do
@@ -127,16 +126,16 @@ module Backend = struct
         else Ok a )
     | _ ->
       (* A symbolic expression is valid, but we print to check if Ptr's are passing through here  *)
-      Log.debug2 "Saw a symbolic address: %a@." Expr.pp a;
+      Log.debug2 "Saw a symbolic address: %a@." Smtml.Expr.pp a;
       return (Ok a)
 
   let ptr v =
     let open Symbolic_choice_without_memory in
-    match Expr.view v with
+    match Smtml.Expr.view v with
     | Ptr { base; _ } -> return base
     | _ ->
-      Log.debug2 {|free: cannot fetch pointer base of "%a"|} Expr.pp v;
-      let* () = add_pc @@ Expr.value False in
+      Log.debug2 {|free: cannot fetch pointer base of "%a"|} Smtml.Expr.pp v;
+      let* () = add_pc @@ Smtml.Expr.value False in
       assert false
 
   let free m p =
@@ -151,7 +150,7 @@ module Backend = struct
     let open Symbolic_choice_without_memory in
     let+ base = address ptr in
     Hashtbl.replace m.chunks base size;
-    Expr.ptr base (Symbolic_value.const_i32 0l)
+    Smtml.Expr.ptr base (Symbolic_value.const_i32 0l)
 end
 
 include Symbolic_memory_make.Make (Backend)