diff --git a/txpipe-base/Dockerfile b/txpipe-base/Dockerfile
index 6dae35e..7a5c57a 100644
--- a/txpipe-base/Dockerfile
+++ b/txpipe-base/Dockerfile
@@ -1,7 +1,7 @@
 FROM condaforge/mambaforge:23.3.1-1
 LABEL maintainer=joezuntz@googlemail.com
 
-ENV TX_MPI_VERSION=4.0.2
+ENV TX_MPI_VERSION=4.2.0
 
 
 # Make, which we will need for everything
diff --git a/txpipe-dev/Dockerfile b/txpipe-dev/Dockerfile
index 8ebe901..68d5190 100644
--- a/txpipe-dev/Dockerfile
+++ b/txpipe-dev/Dockerfile
@@ -9,7 +9,7 @@ RUN echo Build version 3
 # but apparently not. Might be a github actions thing.
 # or maybe I just didn't wait long enough for the parent
 # build to propagate.
-ENV TX_MPI_VERSION=4.0.2
+ENV TX_MPI_VERSION=4.2.0
 
 ENV SKLEARN_ALLOW_DEPRECATED_SKLEARN_PACKAGE_INSTALL=True
 
@@ -36,7 +36,6 @@ RUN git clone --branch ${TX_TAG_FOR_DEPENDENCIES}  https://github.com/LSSTDESC/T
     && cat ../conda-extras.yml \
     && echo cat environment-piponly.yml \
     && cat environment-piponly.yml \
-    && mamba install https://anaconda.org/conda-forge/mpich/4.0.2/download/linux-64/mpich-4.0.2-external_0.tar.bz2 \
     && mamba env update --name base --file  environment-nopip2.yml \
     && mamba env update --name base --file ../conda-extras.yml \
     && mamba env update --name base --file environment-piponly.yml \