diff --git a/README.md b/README.md
index fabbef1..b05d3b8 100644
--- a/README.md
+++ b/README.md
@@ -27,11 +27,11 @@ If you prefer an email, contact me at `toolleeo@gmail.com`.
 
 # Summary
 
-To date, **699** apps/tools covered, divided in **43** categories.
+To date, **700** apps/tools covered, divided in **43** categories.
 
 # Index
 
-[Backup](#backup) (8) | [Calculators](#calc) (5) | [Chat and instant messaging](#chat) (8) | [Conversion](#conversion) (7) | [Data management](#data-management) (31) | [Data transfer](#transfer) (33) | [Directory changers](#cd) (8) | [Disk usage analyzers](#disk-analyzer) (8) | [Editors](#editors) (21) | [Email](#email) (10) | [File and file system handling](#file-handling) (35) | [File manager](#file-manager) (11) | [File renamers](#file-renamer) (7) | [File systems](#file-system) (3) | [Font management](#font) (2) | [Funny tools](#funny) (18) | [Games](#games) (35) | [Git and accessories](#git) (26) | [Graphics](#graphics) (20) | [Multimedia](#multimedia) (3) | [Networking](#networking) (18) | [Note taking](#note-taking) (14) | [Office tools](#office) (15) | [Organizers and calendars](#organizers) (13) | [Online search and resources](#online) (8) | [Password managers](#password-manager) (11) | [Productivity](#productivity) (24) | [Programming](#programming) (23) | [Science](#science) (8) | [Security and encryption](#security) (14) | [Shells](#shells) (6) | [Sound and music](#music) (24) | [System monitoring](#monitor) (26) | [System tools](#system) (27) | [Terminals](#terminal) (9) | [Text processing](#text-processing) (41) | [Text search](#text-search) (9) | [Todo managers](#todo-manager) (18) | [Utilities](#utility) (30) | [Versioning](#versioning) (6) | [Viewers](#viewers) (27) | [Web browser](#browser) (16) | [Web development](#webdev) (13)
+[Backup](#backup) (8) | [Calculators](#calc) (5) | [Chat and instant messaging](#chat) (8) | [Conversion](#conversion) (7) | [Data management](#data-management) (31) | [Data transfer](#transfer) (33) | [Directory changers](#cd) (8) | [Disk usage analyzers](#disk-analyzer) (8) | [Editors](#editors) (21) | [Email](#email) (10) | [File and file system handling](#file-handling) (35) | [File manager](#file-manager) (11) | [File renamers](#file-renamer) (7) | [File systems](#file-system) (3) | [Font management](#font) (2) | [Funny tools](#funny) (18) | [Games](#games) (35) | [Git and accessories](#git) (26) | [Graphics](#graphics) (20) | [Multimedia](#multimedia) (3) | [Networking](#networking) (18) | [Note taking](#note-taking) (14) | [Office tools](#office) (15) | [Organizers and calendars](#organizers) (14) | [Online search and resources](#online) (8) | [Password managers](#password-manager) (11) | [Productivity](#productivity) (24) | [Programming](#programming) (23) | [Science](#science) (8) | [Security and encryption](#security) (14) | [Shells](#shells) (6) | [Sound and music](#music) (24) | [System monitoring](#monitor) (26) | [System tools](#system) (27) | [Terminals](#terminal) (9) | [Text processing](#text-processing) (41) | [Text search](#text-search) (9) | [Todo managers](#todo-manager) (18) | [Utilities](#utility) (30) | [Versioning](#versioning) (6) | [Viewers](#viewers) (27) | [Web browser](#browser) (16) | [Web development](#webdev) (13)
 
 Some links to [related resources](#resources).
 
@@ -486,6 +486,7 @@ Calendar managers.
 * [ppl addressbook](http://ppladdressbook.org/) - ``ppl`` is free software made out of other free software.  It's built on top of Ruby and Git, and the completely free vcard address book format.
 * [Remind](https://www.roaringpenguin.com/products/remind) - Calendar program with possibility to set complex rules to define events; custom, powerful text-based storage format.
 * [remint](https://sr.ht/~mlaparie/remint/) - A simple terminal UI wrapper for D. Skoll's Remind calendar program
+* [vdirsyncer](https://github.com/pimutils/vdirsyncer) - CalDAV synchronization program.
 * [Wyrd](http://freecode.com/projects/wyrd/) - Curses front-end for [Remind](https://www.roaringpenguin.com/products/remind) written in OCaml with vertically scrollable time table.  
 
 ## <a name="online"></a>Online search and resources
diff --git a/data/apps.csv b/data/apps.csv
index 29a0f71..5636b5e 100644
--- a/data/apps.csv
+++ b/data/apps.csv
@@ -698,3 +698,4 @@ programming,readme-md-generator,,https://github.com/kefranabg/readme-md-generato
 security,StegCloak,,https://github.com/kurolabs/stegcloak,Hide secrets with invisible characters in plain text securely using passwords
 file-manager,fff,,https://github.com/dylanaraps/fff,"Fast, simple file manager written in bash."
 networking,mosh,,https://mosh.org/,Remote SSH client that achieve good responsiveness in presence of intermittent connectivity and roaming.
+organizers,vdirsyncer,,https://github.com/pimutils/vdirsyncer,CalDAV synchronization program.