diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index c2989c3f..aa33920e 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -33,7 +33,7 @@ jobs:
           sudo DEBIAN_FRONTEND=noninteractive apt-get install autoconf automake libtool libgmp-dev libmpfr-dev libqd-dev
       - name: Configure
         run: |
-          ./autogen.sh
+          autoreconf -i
           ./configure --disable-static $CONFIGURE_OPTS
       - name: Compile
         run: make -j $JOBS
diff --git a/configure.ac b/configure.ac
index 79a0b069..0ccc4c48 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,7 +1,7 @@
 # -*- Autoconf -*-
 # Process this file with autoconf to produce a configure script.
 
-AC_PREREQ([2.71])
+AC_PREREQ([2.69])
 AC_INIT([fplll],[5.4.2])
 AC_CONFIG_SRCDIR([fplll/fplll.cpp])
 AM_MAINTAINER_MODE([enable])
@@ -140,16 +140,6 @@ AS_IF([test "x${have_libqd}" = "xyes"], [
 # the AC_SEARCH_LIBS macro works.
 AC_SUBST(LIBQD_LIBS)
 
-# Checks for header files.
-m4_warn([obsolete],
-[The preprocessor macro `STDC_HEADERS' is obsolete.
-  Except in unusual embedded environments, you can safely include all
-  ISO C90 headers unconditionally.])dnl
-# Autoupdate added the next two lines to ensure that your configure
-# script's behavior did not change.  They are probably safe to remove.
-AC_CHECK_INCLUDES_DEFAULT
-AC_PROG_EGREP
-
 AC_CHECK_HEADERS([limits.h cstdio iostream string limits vector])
 
 # Checks for typedefs, structures, and compiler characteristics.