diff --git a/.mill-version b/.mill-version
index d33c3a2..d61567c 100644
--- a/.mill-version
+++ b/.mill-version
@@ -1 +1 @@
-0.12.0
\ No newline at end of file
+0.12.3
\ No newline at end of file
diff --git a/build.sc b/build.sc
index 3ebe25f..30d3ba7 100644
--- a/build.sc
+++ b/build.sc
@@ -14,8 +14,8 @@ object publish extends Cross[Publish](scala213, scala212)
 object Deps {
 
   object Version {
-    def coursier      = "2.1.14"
-    def jsoniterScala = "2.31.1"
+    def coursier      = "2.1.20"
+    def jsoniterScala = "2.31.3"
   }
 
   def collectionCompat = ivy"org.scala-lang.modules::scala-collection-compat::2.12.0"
@@ -25,8 +25,8 @@ object Deps {
     ivy"com.github.plokhotnyuk.jsoniter-scala::jsoniter-scala-core:${Version.jsoniterScala}"
   def jsoniterMacros =
     ivy"com.github.plokhotnyuk.jsoniter-scala::jsoniter-scala-macros:${Version.jsoniterScala}"
-  def sttp  = ivy"com.softwaremill.sttp.client3::core:3.5.1"
-  def utest = ivy"com.lihaoyi::utest::0.7.10"
+  def sttp  = ivy"com.softwaremill.sttp.client3::core:3.10.1"
+  def utest = ivy"com.lihaoyi::utest::0.8.4"
 }
 
 trait Publish extends CrossScalaModule with Published {
diff --git a/mill b/mill
index 52a9e9b..d4594af 100755
--- a/mill
+++ b/mill
@@ -12,7 +12,7 @@
 # Licensed under the Apache License, Version 2.0
 
 
-DEFAULT_MILL_VERSION=0.9.10
+DEFAULT_MILL_VERSION=0.12.3
 
 set -e
 
diff --git a/mill.bat b/mill.bat
index 6523751..d1bdaf6 100644
--- a/mill.bat
+++ b/mill.bat
@@ -15,7 +15,7 @@ rem setlocal seems to be unavailable on Windows 95/98/ME
 rem but I don't think we need to support them in 2019
 setlocal enabledelayedexpansion
 
-set "DEFAULT_MILL_VERSION=0.9.10"
+set "DEFAULT_MILL_VERSION=0.12.3"
 
 set "MILL_REPO_URL=https://github.com/com-lihaoyi/mill"