Comment 7 for bug 2029480

I'm sorry but the related fix seem to be not complete: during upgrade from 23.10.1 mantic to 24.04 noble it updates hplip-data 3.23.12+dfsg0-0ubuntu5 from previous 3.22.10+dfsg0-2ubuntu1 and it doesn't generate SyntaxWarnings... but a few moments later, then during python3 (3.12.3-0ubuntu1) configuration:

Configurando python3 (3.12.3-0ubuntu1) ...
running python rtupdate hooks for python3.12...
...
/usr/share/hplip/base/imagesize.py:186: SyntaxWarning: invalid escape sequence '\#'
  re.compile('\#define\s+\S+\s+\d+') : ('image/x-xbitmap', xbmsize),
/usr/share/hplip/base/imagesize.py:187: SyntaxWarning: invalid escape sequence '\/'
  re.compile('\/\* XPM \*\/') : ('image/x-xpixmap', xpmsize),
/usr/share/hplip/base/imagesize.py:189: SyntaxWarning: invalid escape sequence '\*'
  re.compile('^II\*\x00') : ('image/tiff', tiffsize),
/usr/share/hplip/fax/ledmfax.py:46: SyntaxWarning: invalid escape sequence '\d'
  http_result_pat = re.compile(b"""HTTP/\d.\d\s(\d+)""", re.I)
...
running python post-rtupdate hooks for python3.12...

You can also reinstall hplip-data using apt and ending in the same problem:

# apt install --reinstall hplip-data
Leyendo lista de paquetes... Hecho
Creando árbol de dependencias... Hecho
Leyendo la información de estado... Hecho
0 actualizados, 0 nuevos se instalarán, 1 reinstalados, 0 para eliminar y 0 no actualizados.
Se necesita descargar 6.467 kB de archivos.
Se utilizarán 0 B de espacio de disco adicional después de esta operación.
Des:1 http://ports.ubuntu.com/ubuntu-ports noble/main arm64 hplip-data all 3.23.12+dfsg0-0ubuntu5 [6.467 kB]
Descargados 6.467 kB en 1s (8.035 kB/s)
(Leyendo la base de datos ... 221724 ficheros o directorios instalados actualmente.)
Preparando para desempaquetar .../hplip-data_3.23.12+dfsg0-0ubuntu5_all.deb ...
Desempaquetando hplip-data (3.23.12+dfsg0-0ubuntu5) sobre (3.23.12+dfsg0-0ubuntu5) ...
Configurando hplip-data (3.23.12+dfsg0-0ubuntu5) ...
/usr/share/hplip/base/imagesize.py:186: SyntaxWarning: invalid escape sequence '\#'
  re.compile('\#define\s+\S+\s+\d+') : ('image/x-xbitmap', xbmsize),
/usr/share/hplip/base/imagesize.py:187: SyntaxWarning: invalid escape sequence '\/'
  re.compile('\/\* XPM \*\/') : ('image/x-xpixmap', xpmsize),
/usr/share/hplip/base/imagesize.py:189: SyntaxWarning: invalid escape sequence '\*'
  re.compile('^II\*\x00') : ('image/tiff', tiffsize),
/usr/share/hplip/fax/ledmfax.py:46: SyntaxWarning: invalid escape sequence '\d'
  http_result_pat = re.compile(b"""HTTP/\d.\d\s(\d+)""", re.I)