diff --git a/Dockerfile b/Dockerfile
index 7450ee6..c32cc31 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 FROM ubuntu:20.04
 
 ARG MPLABX_VERSION=5.45
-ARG XC8_VERSION=2.20
+ARG XC8_VERSION=1.34
 
 # Install the dependencies
 # See https://microchipdeveloper.com/install:mplabx-lin64
diff --git a/README.md b/README.md
index 652fa9c..4c022d4 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ This action will build a MPLAB X / XC8 project.
 It runs on Linux Ubuntu 20.04 and uses:
 
 * [MPLAB X](https://www.microchip.com/en-us/development-tools-tools-and-software/mplab-x-ide) v5.45
-* [XC8](https://www.microchip.com/en-us/development-tools-tools-and-software/mplab-xc-compilers) v2.20
+* [XC8](https://www.microchip.com/en-us/development-tools-tools-and-software/mplab-xc-compilers) v1.34
 
 ## Inputs
 
diff --git a/build.sh b/build.sh
index 8cc5d18..58f5034 100755
--- a/build.sh
+++ b/build.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-echo "Building project $1:$2 with MPLAB X v5.45 and XC8 v2.20"
+echo "Building project $1:$2 with MPLAB X v5.45 and XC8 v1.34"
 
 set -x -e