diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 4a65b70..3c4492e 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -13,11 +13,19 @@
 
 == Unreleased changes (release date TBD)
 
+https://github.com/oxidecomputer/progenitor/compare/v0.4.0\...HEAD[Full list of commits]
+
+== 0.4.0 (released 2023-09-25)
+
+https://github.com/oxidecomputer/progenitor/compare/v0.4.0\...v0.4.0[Full list of commits]
+
+== 0.4.0 (released 2023-09-25)
+
 * Support for updated dropshot pagination extension (#465)
 * Many CLI and http mock generation improvements (beta)
 * Add cargo-progenitor (#476)
 
-https://github.com/oxidecomputer/progenitor/compare/v0.3.0\...HEAD[Full list of commits]
+https://github.com/oxidecomputer/progenitor/compare/v0.3.0\...v0.4.0[Full list of commits]
 
 == 0.3.0 (released 2023-05-03)
 
diff --git a/Cargo.lock b/Cargo.lock
index d46ffec..f5852ef 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -249,7 +249,7 @@ dependencies = [
 
 [[package]]
 name = "cargo-progenitor"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "anyhow",
  "built",
@@ -1397,7 +1397,7 @@ dependencies = [
 
 [[package]]
 name = "progenitor"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "base64",
  "chrono",
@@ -1417,7 +1417,7 @@ dependencies = [
 
 [[package]]
 name = "progenitor-client"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "bytes",
  "futures-core",
@@ -1430,7 +1430,7 @@ dependencies = [
 
 [[package]]
 name = "progenitor-impl"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "dropshot",
  "expectorate",
@@ -1456,7 +1456,7 @@ dependencies = [
 
 [[package]]
 name = "progenitor-macro"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "openapiv3",
  "proc-macro2",
diff --git a/cargo-progenitor/Cargo.toml b/cargo-progenitor/Cargo.toml
index 928a8d4..d415562 100644
--- a/cargo-progenitor/Cargo.toml
+++ b/cargo-progenitor/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "cargo-progenitor"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2021"
 license = "MPL-2.0"
 description = "A cargo command to generate a Rust client SDK from OpenAPI"
@@ -11,9 +11,9 @@ categories = ["api-bindings", "development-tools::cargo-plugins"]
 build = "build.rs"
 
 [dependencies]
-progenitor = { version = "0.3.0", path = "../progenitor" }
-progenitor-client = { version = "0.3.0", path = "../progenitor-client" }
-progenitor-impl = { version = "0.3.0", path = "../progenitor-impl" }
+progenitor = { version = "0.4.0", path = "../progenitor" }
+progenitor-client = { version = "0.4.0", path = "../progenitor-client" }
+progenitor-impl = { version = "0.4.0", path = "../progenitor-impl" }
 anyhow = "1.0"
 clap = { version = "4.4.4", features = ["derive"] }
 env_logger = "0.10.0"
diff --git a/progenitor-client/Cargo.toml b/progenitor-client/Cargo.toml
index 994b33d..9fd28df 100644
--- a/progenitor-client/Cargo.toml
+++ b/progenitor-client/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "progenitor-client"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2021"
 license = "MPL-2.0"
 repository = "https://github.com/oxidecomputer/progenitor.git"
diff --git a/progenitor-impl/Cargo.toml b/progenitor-impl/Cargo.toml
index 1db82a1..30872d1 100644
--- a/progenitor-impl/Cargo.toml
+++ b/progenitor-impl/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "progenitor-impl"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2021"
 license = "MPL-2.0"
 description = "An OpenAPI client generator - core implementation"
diff --git a/progenitor-macro/Cargo.toml b/progenitor-macro/Cargo.toml
index 0f391f7..fd3c970 100644
--- a/progenitor-macro/Cargo.toml
+++ b/progenitor-macro/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "progenitor-macro"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2021"
 license = "MPL-2.0"
 description = "An OpenAPI client generator - macros"
@@ -13,7 +13,7 @@ proc-macro = true
 [dependencies]
 openapiv3 = "1.0.3"
 proc-macro2 = "1.0"
-progenitor-impl = { version = "0.3.0", path = "../progenitor-impl" }
+progenitor-impl = { version = "0.4.0", path = "../progenitor-impl" }
 quote = "1.0"
 schemars = "0.8.12"
 serde = { version = "1.0", features = ["derive"] }
diff --git a/progenitor/Cargo.toml b/progenitor/Cargo.toml
index 62fb106..1a597cc 100644
--- a/progenitor/Cargo.toml
+++ b/progenitor/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "progenitor"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2021"
 license = "MPL-2.0"
 description = "An OpenAPI client generator"
@@ -10,9 +10,9 @@ keywords = ["openapi", "openapiv3", "sdk", "generator", "proc_macro"]
 categories = ["api-bindings", "compilers"]
 
 [dependencies]
-progenitor-client = { version = "0.3.0", path = "../progenitor-client" }
-progenitor-impl = { version = "0.3.0", path = "../progenitor-impl" }
-progenitor-macro = { version = "0.3.0", path = "../progenitor-macro" }
+progenitor-client = { version = "0.4.0", path = "../progenitor-client" }
+progenitor-impl = { version = "0.4.0", path = "../progenitor-impl" }
+progenitor-macro = { version = "0.4.0", path = "../progenitor-macro" }
 serde_json = "1.0"
 
 [dev-dependencies]