diff --git a/PackageInfo.g b/PackageInfo.g
index d54c163..122aa93 100644
--- a/PackageInfo.g
+++ b/PackageInfo.g
@@ -10,9 +10,9 @@ SetPackageInfo( rec(
 
 PackageName := "HeckeCategories",
 Subtitle := "Categorification of Hecke algebras",
-Version := "2023.02-03",
+Version := "2023.02-04",
 
-Date := Concatenation( "01/", ~.Version{[ 6, 7 ]}, "/", ~.Version{[ 1 .. 4 ]} ),
+Date := (function ( ) if IsBound( GAPInfo.SystemEnvironment.GAP_PKG_RELEASE_DATE ) then return GAPInfo.SystemEnvironment.GAP_PKG_RELEASE_DATE; else return Concatenation( ~.Version{[ 1 .. 4 ]}, "-", ~.Version{[ 6, 7 ]}, "-01" ); fi; end)( ),
 License := "GPL-2.0-or-later",
 
 Persons := [
diff --git a/dev/.release b/dev/.release
index d71a674..00b11b8 100644
--- a/dev/.release
+++ b/dev/.release
@@ -6,13 +6,6 @@
 
 set -e
 
-# adjust date
-# Note that we cannot use sed's `-i` option for in-place editing, as
-# that is a non-portable extension of POSIX, which works differently in
-# BSD and GNU make.
-sed "s;Date := .*;Date := \"$(date +%d/%m/%Y)\",;" PackageInfo.g > PackageInfo.g.bak
-mv PackageInfo.g.bak PackageInfo.g
-
 # replace links to packages which are possibly referenced in the documentation, keep this in sync with `Tests.yml.j2`
 for package in CAP_project/CAP CAP_project/CompilerForCAP CAP_project/MonoidalCategories CAP_project/CartesianCategories CAP_project/FreydCategoriesForCAP HigherHomologicalAlgebra/ToolsForHigherHomologicalAlgebra homalg_project/homalg homalg_project/Modules CategoricalTowers/CategoryConstructor CategoricalTowers/Toposes; do
     
@@ -27,5 +20,9 @@ for package in CAP_project/CAP CAP_project/CompilerForCAP CAP_project/MonoidalCa
     
 done
 
+if [ "$PDFFiles" != "doc/manual.pdf" ] ; then
+    error "PackageDoc set to $PDFFiles but expected doc/manual.pdf"
+fi
+
 # remove dev directory
 rm -rf dev
diff --git a/dev/make_dist.sh b/dev/make_dist.sh
index efd915e..6c2bf9d 100755
--- a/dev/make_dist.sh
+++ b/dev/make_dist.sh
@@ -2,4 +2,4 @@
 
 set -e
 
-./dev/release-gap-package --skip-existing-release --release-script dev/.release
+GAP_PKG_RELEASE_DATE=$(date -I) ./dev/release-gap-package --skip-existing-release --release-script dev/.release
diff --git a/dev/release-gap-package b/dev/release-gap-package
index 9f1e177..e18b552 100755
--- a/dev/release-gap-package
+++ b/dev/release-gap-package
@@ -673,7 +673,7 @@ echo ""
 
 for PDFFile in $PDFFiles ; do
     FULLNAME="$TMP_DIR/$BASENAME/$PDFFile"
-    UPLOADNAME=$(echo "${PDFFile#doc/}" | sed 's;/;-;g')
+    UPLOADNAME=$PKG-$VERSION-$(echo "${PDFFile#doc/}" | sed 's;/;-;g')
     if [ ! -f "$FULLNAME" ] ; then
         error "could not find PDF"
     fi
diff --git a/dev/simulate_dist.sh b/dev/simulate_dist.sh
index f49d7c2..95ef51f 100755
--- a/dev/simulate_dist.sh
+++ b/dev/simulate_dist.sh
@@ -2,4 +2,4 @@
 
 set -e
 
-./dev/release-gap-package --release-script dev/.release --only-tarball
+GAP_PKG_RELEASE_DATE=$(date -I) ./dev/release-gap-package --release-script dev/.release --only-tarball