diff --git a/.changelog/unreleased/breaking-changes/166-protojson-support.md b/.changelog/unreleased/breaking-changes/166-protojson-support.md
deleted file mode 100644
index 98671c29..00000000
--- a/.changelog/unreleased/breaking-changes/166-protojson-support.md
+++ /dev/null
@@ -1,2 +0,0 @@
-- Added protojson support
-  ([#166](https://github.com/cosmos/ibc-proto-rs/pull/166)). Feature flag `serde` now abides by [protobuf json rules](https://protobuf.dev/programming-guides/proto3/#json) when it comes to json serialization/deserialization.
diff --git a/.changelog/v0.40.0/breaking-changes/166-protojson-support.md b/.changelog/v0.40.0/breaking-changes/166-protojson-support.md
new file mode 100644
index 00000000..a94d06fa
--- /dev/null
+++ b/.changelog/v0.40.0/breaking-changes/166-protojson-support.md
@@ -0,0 +1,4 @@
+- Added ProtoJSON support.
+  The `serde` feature flag now abides by [Protobuf JSON rules](https://protobuf.dev/programming-guides/proto3/#json)
+  when it comes to JSON serialization/deserialization.
+  ([#166](https://github.com/cosmos/ibc-proto-rs/pull/166))
diff --git a/.changelog/v0.40.0/summary.md b/.changelog/v0.40.0/summary.md
new file mode 100644
index 00000000..82752295
--- /dev/null
+++ b/.changelog/v0.40.0/summary.md
@@ -0,0 +1 @@
+*December 29th, 2023*
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 19544f19..3831bcc1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,16 @@
 # CHANGELOG
 
+## v0.40.0
+
+*December 29th, 2023*
+
+### BREAKING CHANGES
+
+- Added ProtoJSON support.
+  The `serde` feature flag now abides by [Protobuf JSON rules](https://protobuf.dev/programming-guides/proto3/#json)
+  when it comes to JSON serialization/deserialization.
+  ([#166](https://github.com/cosmos/ibc-proto-rs/pull/166))
+
 ## v0.39.1
 
 *November 22nd, 2023*
diff --git a/Cargo.toml b/Cargo.toml
index d7ae3649..f2a09989 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name         = "ibc-proto"
-version      = "0.39.1"
+version      = "0.40.0"
 authors      = ["Informal Systems <hello@informal.systems>"]
 edition      = "2021"
 license      = "Apache-2.0"
@@ -37,7 +37,7 @@ subtle-encoding        = { version = "0.5",  default-features = false }
 base64                 = { version = "0.21", default-features = false, features = ["alloc"] }
 flex-error             = { version = "0.4",  default-features = false }
 ics23                  = { version = "0.11.0", default-features = false }
-informalsystems-pbjson = { version = "0.6.0", optional = true, default-features = false }
+informalsystems-pbjson = { version = "0.7.0", optional = true, default-features = false }
 
 ## Optional: enabled by the `parity-scale-codec` feature
 parity-scale-codec = { version = "3.0.0", default-features = false, features = ["full"],   optional = true }