diff --git a/linol-lwt.opam b/linol-lwt.opam
index ada08ca7..10599a47 100644
--- a/linol-lwt.opam
+++ b/linol-lwt.opam
@@ -13,9 +13,8 @@ build: [
 depends: [
   "dune" { >= "2.0" }
   "linol" { = version }
-  "lsp" { >= "1.4" & < "1.6" }
-  "jsonrpc" { >= "1.4" & < "1.6" }
-  "containers" { >= "3.0" & < "4.0" }
+  "lsp" { >= "1.6" & < "1.7" }
+  "jsonrpc" { >= "1.6" & < "1.7" }
   "lwt" { >= "5.1" & < "6.0" }
   "base-unix"
   "yojson" { >= "1.6" }
diff --git a/linol.opam b/linol.opam
index 266786e4..e3cd7f4a 100644
--- a/linol.opam
+++ b/linol.opam
@@ -12,7 +12,6 @@ build: [
 ]
 depends: [
   "dune" { >= "2.0" }
-  "containers" { >= "3.0" & < "4.0" }
   "yojson" { >= "1.6" }
   "logs"
   "lsp" { >= "1.4" & < "1.6" }
diff --git a/src/dune b/src/dune
index 1354e047..3ad6710b 100644
--- a/src/dune
+++ b/src/dune
@@ -3,4 +3,4 @@
   (name linol)
   (public_name linol)
   (flags :standard -warn-error -a+8)
-  (libraries containers yojson lsp logs))
+  (libraries yojson lsp logs))
diff --git a/src/jsonrpc2.ml b/src/jsonrpc2.ml
index 6877dc9d..eb6ff715 100644
--- a/src/jsonrpc2.ml
+++ b/src/jsonrpc2.ml
@@ -2,7 +2,6 @@
 (** {1 Simple JSON-RPC2 implementation}
     See {{: https://www.jsonrpc.org/specification} the spec} *)
 
-module Fmt = CCFormat
 module J = Yojson.Safe
 module Err = Jsonrpc.Response.Error
 
@@ -125,7 +124,9 @@ module Make(IO : IO)
         end
     in
     let*? headers = read_headers [] in
-    Log.debug (fun k->k "jsonrpc2: read headers: %a" Fmt.Dump.(list @@ pair string string) headers);
+    Log.debug (fun k->k "jsonrpc2: read headers: [%s]"
+                  (String.concat ";" @@
+                   List.map (fun (a,b)->Printf.sprintf "(%S,%S)" a b) headers));
     let ok = match List.assoc "content-type" headers with
       | "utf8" | "utf-8" -> true
       | _ -> false
diff --git a/src/lwt/dune b/src/lwt/dune
index 23acaeb5..183e0863 100644
--- a/src/lwt/dune
+++ b/src/lwt/dune
@@ -2,5 +2,5 @@
 (library
   (name linol_lwt)
   (public_name linol-lwt)
-  (libraries yojson containers lwt lwt.unix linol lsp jsonrpc)
+  (libraries yojson lwt lwt.unix linol lsp jsonrpc)
   (flags :standard -warn-error -a))