diff --git a/srcpkgs/giac/template b/srcpkgs/giac/template
index da344887eb6..dd94525328a 100644
--- a/srcpkgs/giac/template
+++ b/srcpkgs/giac/template
@@ -1,8 +1,8 @@
 # Template file for 'giac'
 pkgname=giac
-version=1.4.9r71
+version=1.5.0.27
 revision=1
-wrksrc="${pkgname}-${version/r*}"
+wrksrc="giac-${version%.*}"
 build_style=gnu-configure
 makedepends="fltk-devel gmp-devel gsl-devel lapack-devel
  libjpeg-turbo-devel libpng-devel readline-devel"
@@ -11,8 +11,8 @@ short_desc="Free computer algebra system"
 maintainer="Orphaned <orphan@voidlinux.eu>"
 license="GPL-3.0-or-later"
 homepage="https://www-fourier.ujf-grenoble.fr/~parisse/giac.html"
-distfiles="https://www-fourier.ujf-grenoble.fr/~parisse/debian/dists/stable/main/source/giac_${version/r/-}.tar.gz"
-checksum=e90376af955da92a8e35e333cb94132b9d4a697eec7634cc4403cf3c7b965046
+distfiles="https://www-fourier.ujf-grenoble.fr/~parisse/debian/dists/stable/main/source/giac_${version%.*}-${version##*.}.tar.gz"
+checksum=23ba720efb6c6a3a898579a8ab3150a9708184ce74065d9904c6fa38d85f6f71
 
 post_install() {
 	# remove duplicates
diff --git a/srcpkgs/giac/update b/srcpkgs/giac/update
new file mode 100644
index 00000000000..9eaba5ef293
--- /dev/null
+++ b/srcpkgs/giac/update
@@ -0,0 +1 @@
+pattern='(?<!-)\b\Q'"$pkgname"'\E[-_]?((src|source)[-_])?\K([^/_\s]*?\d[^/_\s]*?)(?=(?:[-_.](?:src|source|orig))?\.(?:[jt]ar|shar|t[bglx]z|tbz2|zip))\b'