diff --git a/build/pkgs/ptyprocess/checksums.ini b/build/pkgs/ptyprocess/checksums.ini
index d55046be142..7c8cf7bd652 100644
--- a/build/pkgs/ptyprocess/checksums.ini
+++ b/build/pkgs/ptyprocess/checksums.ini
@@ -1,5 +1,5 @@
 tarball=ptyprocess-VERSION.tar.gz
-sha1=2d8830d1025c8e33149c7723c2f283122f9488c1
-md5=9da200c397cb1752209a6b718b6cfc68
-cksum=2094263560
+sha1=3290062d67ef8a2f136bff9c2cd106673ff21316
+md5=94e537122914cc9ec9c1eadcd36e73a1
+cksum=1748633415
 upstream_url=https://pypi.io/packages/source/p/ptyprocess/ptyprocess-VERSION.tar.gz
diff --git a/build/pkgs/ptyprocess/dependencies b/build/pkgs/ptyprocess/dependencies
index 97701a95eec..15df0c4d6d8 100644
--- a/build/pkgs/ptyprocess/dependencies
+++ b/build/pkgs/ptyprocess/dependencies
@@ -1,4 +1,4 @@
-$(PYTHON) | $(PYTHON_TOOLCHAIN) flit_core toml
+$(PYTHON) | $(PYTHON_TOOLCHAIN)
 
 ----------
 All lines of this file are ignored except the first.
diff --git a/build/pkgs/ptyprocess/install-requires.txt b/build/pkgs/ptyprocess/install-requires.txt
index 1f0ce3f011d..de89260872b 100644
--- a/build/pkgs/ptyprocess/install-requires.txt
+++ b/build/pkgs/ptyprocess/install-requires.txt
@@ -1 +1,3 @@
-ptyprocess >=0.5.1
+ptyprocess ==0.5.1
+# https://trac.sagemath.org/ticket/31280#comment:42 and following
+# sagelib is not compatible with ptyprocess 0.5.2, 0.6, and 0.7
diff --git a/build/pkgs/ptyprocess/package-version.txt b/build/pkgs/ptyprocess/package-version.txt
index faef31a4357..dfd7f4b3ab3 100644
--- a/build/pkgs/ptyprocess/package-version.txt
+++ b/build/pkgs/ptyprocess/package-version.txt
@@ -1 +1 @@
-0.7.0
+0.5.1.p0