failure to create catalog in epub format with R 5.0 and 5.01

[Frank N]

getting this error, before upgrade had no issues

calibre, version 5.0.1 (win32, embedded-python: True)
Conversion error: Mislukt: Catalogus aanmaken

Catalogus aanmaken
 Sections: Authors, Titles, Series, Recently Added, Descriptions
Catalog_EPUB_MOBI('calibre_dell_nw'): Generating epub for generic_eink in GUI environment, locale: 'Dutch'
 connected_device: 'None'
 book count: 665
 opts:
  author_clip: 100
  catalog_title: 'Mijn boeken'
  connected_kindle: False
  creator: 'zondag, september 27, 2020'
  cross_reference_authors: True
  description_clip: 380
  exclude_genre: '\\[.+\\]|^\\+$'
  exclusion_rules: ()
  fmt: 'epub'
  genre_source_field: 'Labels'
  header_note_source_field: ''
  merge_comments_rule: '::True'
  output_profile: 'generic_eink'
  prefix_rules: ()
  search_text: None
  sort_by: None
  sort_descriptions_by_author: True
  sync: False
  thumb_width: '1.00'
  use_existing_cover: False
 Begin catalog source generation (0:00:00)
 Custom fields:
  #fysiekbk 'Ja/Nee' bool
  #isbn 'ISBN' composite
  #kast 'kast' enumeration
  #nr 'nr' text
  #plank2 'plank2' enumeration
  #prijs_betaald 'prijs_betaald' text
  #prijs_verkoop_exverz 'prijs_verkoop_exverz' float
  #prijsnw 'prijsnw' text
 Thumbnails:
  DPI = 168; thumbnail dimensions: 168 x 224
  existing thumb cache at C:\Users\Dell\AppData\Local\calibre-cache\catalog\thumbs.zip, cached_thumb_width: 1.00"
Titels aan het sorteren (0:00:01)
Gegevensbank aan het sorteren (0:00:01)
Miniatuurweergaves (0:00:01)
Omschrijvingen HTML (0:00:07)
 unhandled exception in catalog generator
Traceback (most recent call last):
  File "runpy.py", line 194, in _run_module_as_main
  File "runpy.py", line 87, in _run_code
  File "site.py", line 89, in <module>
  File "site.py", line 84, in main
  File "site.py", line 55, in run_entry_point
  File "site-packages\calibre\utils\ipc\worker.py", line 215, in main
  File "site-packages\calibre\gui2\convert\gui_conversion.py", line 81, in gui_catalog
  File "site-packages\calibre\library\catalogs\epub_mobi.py", line 407, in run
  File "site-packages\calibre\library\catalogs\epub_mobi_builder.py", line 322, in build_sources
  File "site-packages\calibre\library\catalogs\epub_mobi_builder.py", line 2868, in generate_html_descriptions
  File "site-packages\calibre\library\catalogs\epub_mobi_builder.py", line 2787, in generate_html_description_header
TypeError: '>' not supported between instances of 'NoneType' and 'str'

[Kovid Goyal (kovid)]

Fixed in branch master. The fix will be in the next release. calibre is usually released every alternate Friday.

 status fixreleased

[Frank N (frankien)]

thanks