See ChangeLog: Sat Jan 9 16:02:23 CET 1999 Werner Koch

debian/preinst

@@ -0,0 +1,47 @@
+#!/bin/sh
+
+set -e
+
+case "$1" in
+    upgrade|install)
+	# Try to gracefully handle upgrades from a pre-0.3.3 version
+
+	if [ ! -z $2 ]; then
+	    set +e
+	    dpkg --compare-versions $2 \<= 0.3.2-1
+	    result=$?
+	    set -e
+	    if [ $result = 0 ]; then
+		cat <<EOF
+Due to a bug in the way secret keys were encrypted in versions prior
+to 0.3.3, this version of gnupg is not backwards compatible with $2
+which you have (had) installed on your system.  
+
+There is an upgrade strategy (see /usr/doc/gnupg/NEWS.gz after this
+version is installed), but it requires an old copy of the gpg and gpgm
+EOF
+		echo -n "binaries; shall I make copies of them for you (Y/n)? "
+		read answer
+		if [ ! "$answer" = "n" -a ! "$answer" = "N" ]; then
+		    cp /usr/bin/gpg /usr/bin/gpg.old
+		    cp /usr/bin/gpgm /usr/bin/gpgm.old
+		    echo "Okay, done.  The old versions are /usr/bin/gpg*.old"
+		else
+		    echo "Okay, I haven't made backups."
+		fi;	
+		cat <<EOF
+
+If at any stage you need a pre-0.3.3 gnupg, you can find source and
+binaries for i386, m68k, alpha, powerpc and hurd-i386 at 
+
+   http://james.nocrew.org/gnupg/
+
+Press return to continue
+EOF
+		read foo
+	    fi;
+	fi;
+	;;
+    abort-upgrade)
+	;;
+esac