diff --git a/Dockerfile b/Dockerfile
index 698497e..de52b40 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -64,7 +64,7 @@ RUN apt update -y && apt install -y odbcinst1debian2 && \
     dpkg -i libmyodbc.deb && \
     rm -rf /var/lib/apt/lists/*
 
-ENV ASTERISK_VERSION=18.19.0
+ENV ASTERISK_VERSION=20.4.0
 
 COPY build-asterisk.sh /build-asterisk
 RUN DEBIAN_FRONTEND=noninteractive /build-asterisk
diff --git a/README.md b/README.md
index 66f8556..a738487 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 [![Release](https://github.com/lucasvs/docker-asterisk/actions/workflows/release.yml/badge.svg)](https://github.com/lucasvs/docker-asterisk/actions/workflows/release.yml)
 
-Dockerfile to build [Asterisk](https://github.com/asterisk/asterisk) 18.19.0 with PJSIP Realtime.
+Dockerfile to build [Asterisk](https://github.com/asterisk/asterisk) 20.4.0 with PJSIP Realtime.
 
 ### Includes
  - Pjproject-bundled