diff --git a/flake.lock b/flake.lock
index 47ffa89..40c861d 100644
--- a/flake.lock
+++ b/flake.lock
@@ -7,11 +7,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1685438474,
-        "narHash": "sha256-qQLHbg3mHYgWA3ngvWgWIdsirVkYA0StzKR3Qi72uWg=",
+        "lastModified": 1688552611,
+        "narHash": "sha256-pV/1/AU1l5CNFeKmdJ1jofcaKHhtKAbxY4gazeCyoSo=",
         "owner": "nix-community",
         "repo": "home-manager",
-        "rev": "9f82227b64245c273d98dd02dedd44fc7576041e",
+        "rev": "b23c7501f7e0a001486c9a5555a6c53ac7b08e85",
         "type": "github"
       },
       "original": {
@@ -22,11 +22,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1685383865,
-        "narHash": "sha256-3uQytfnotO6QJv3r04ajSXbEFMII0dUtw0uqYlZ4dbk=",
+        "lastModified": 1688590700,
+        "narHash": "sha256-ZF055rIUP89cVwiLpG5xkJzx00gEuuGFF60Bs/LM3wc=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "5e871d8aa6f57cc8e0dc087d1c5013f6e212b4ce",
+        "rev": "f292b4964cb71f9dfbbd30dc9f511d6165cd109b",
         "type": "github"
       },
       "original": {
diff --git a/home/R.nix b/home/R.nix
index 2b39279..21924b5 100644
--- a/home/R.nix
+++ b/home/R.nix
@@ -30,21 +30,21 @@
           src = builtins.fetchGit {
             url = "ssh://git@ktiu.net/home/git/goethR/";
             ref = "main";
-            rev = "93970916e669e81ffea2ded708d3e95b004f5f5d";
+            rev = "d7e9c54a3a193979ea4195ac36938aa55cd5360f";
           };
           propagatedBuildInputs = [];
           nativeBuildInputs = [];
         };
-        readODS = pkgs.rPackages.buildRPackage {
-          name = "goethR";
-          src = builtins.fetchGit {
-            url = "https://git@github.com/ktiu/readODS/";
-            ref = "v1.8";
-            rev = "03a194bac87b050c42d0e70c8cc638be79c6443d";
-          };
-          propagatedBuildInputs = [xml2 cellranger readr stringi purrr zip];
-          nativeBuildInputs = [];
-        };
+        # readODS = pkgs.rPackages.buildRPackage {
+        #   name = "goethR";
+        #   src = builtins.fetchGit {
+        #     url = "https://git@github.com/ktiu/readODS/";
+        #     ref = "v1.8";
+        #     rev = "d7e9c54a3a193979ea4195ac36938aa55cd5360f";
+        #   };
+        #   propagatedBuildInputs = [xml2 cellranger readr stringi purrr zip];
+        #   nativeBuildInputs = [];
+        # };
       in [
         bookdown
         catmaply
diff --git a/home/calendars/default.nix b/home/calendars/default.nix
new file mode 100644
index 0000000..7098830
--- /dev/null
+++ b/home/calendars/default.nix
@@ -0,0 +1,83 @@
+{ config, pkgs, ... }:
+
+let
+  baikalRemote = slug: {
+    passwordCommand = [ "secret-tool" "lookup" "server" "baikal.ktiu.net" "account" "till" ];
+    userName = "till";
+    type = "caldav";
+    url = "https://baikal.ktiu.net/dav.php/calendars/till/${slug}";
+  };
+  calDefaults = { 
+    # khal.enable = true;
+    local = {
+      type = "filesystem";
+      fileExt = ".ics";
+    };
+    vdirsyncer.enable = true;
+  };
+
+in
+
+{
+  xdg.configFile."khal/config".source = ./khal.config;
+  services.vdirsyncer.enable = true;
+  programs.vdirsyncer.enable = true;
+  # programs.khal = {
+  #   enable = true;
+  #   locale = {
+  #     timefomat          = "%H:%M";
+  #     dateformat         = "%d %b";
+  #     longdateformat     = "%d %b %Y";
+  #     datetimeformat     = "%d %b %H:%M";
+  #     longdatetimeformat = "%d %b %Y %H:%M";
+  #     weeknumbers        = "left";
+  #   };
+  # };
+
+  accounts.calendar.basePath = "${config.xdg.dataHome}/calendars";
+  accounts.calendar.accounts = {
+    till = calDefaults // {
+      # primary = true;
+      # khal.color = "light blue";
+      remote = baikalRemote "default";
+    };
+    mitlisa = calDefaults // {
+      # khal.color = "light magenta";
+      remote = baikalRemote "75db196d-bc81-4de3-96dc-d4c068c1234b";
+    };
+    family = calDefaults // {
+      # khal.color = "dark magenta";
+      remote = baikalRemote "867d77c5-088f-4617-aeb8-6c9a18925e30";
+    };
+    bdays = calDefaults // {
+      # khal.color = "yellow";
+      remote = baikalRemote "geburtstage";
+    };
+    polit = calDefaults // {
+      # khal.color = "dark gray";
+      remote = baikalRemote "polit";
+    };
+    ihg = {
+       # khal.color = "dark cyan";
+       khal.type = "calendar";
+       remote = {
+         type = "http";
+         url  = "https://geocom.uni-frankfurt.de/radicale/ihg/5012a739-dbaf-334b-f093-8db1860bc26e/";
+       };
+    };
+    "mittelbau" = {
+      # khal.color = "light cyan";
+      remote = {
+        type = "http";
+        url  = "https://geocom.uni-frankfurt.de/radicale/ihg/d806b31d-dd3d-9d97-d3e5-f179addeb60a/";
+      };
+    };
+    "eintracht" = {
+      # khal.color = "light red";
+      remote = {
+        type = "http";
+        url  = "http://i.cal.to/ical/257/eintrachtfrankfurt/spielplan/6b9cf611.1d2ac477-36f832c0.ics";
+      };
+    };
+  };
+}
diff --git a/home/calendars/khal.config b/home/calendars/khal.config
new file mode 100644
index 0000000..59b7227
--- /dev/null
+++ b/home/calendars/khal.config
@@ -0,0 +1,62 @@
+# vim:ft=cfg
+[default]
+
+default_calendar     = till
+highlight_event_days = true
+timedelta            = 5d
+print_new            = event
+
+[calendars]
+
+[[till]]
+path = ~/.local/share/calendars/till
+color = light blue
+
+[[mitlisa]]
+path  = ~/.local/share/calendars/mitlisa
+color = light magenta
+
+[[family]]
+path  = ~/.local/share/calendars/family
+color = dark magenta
+
+[[bdays]]
+path  = ~/.local/share/calendars/bdays
+color = yellow
+
+[[mittelbau]]
+path  = ~/.local/share/calendars/mittelbau
+color = light cyan
+
+[[ihg]]
+path  = ~/.local/share/calendars/ihg
+color = dark cyan
+
+[[polit]]
+path  = ~/.local/share/calendars/polit
+color = dark gray
+
+[[holidays]]
+path  = ~/.local/share/calendars/feiertage
+color = light green
+
+[[eintracht]]
+path  = ~/.local/share/calendars/eintracht
+color = light red
+
+[locale]
+timeformat         = %H:%M
+dateformat         = %d %b
+longdateformat     = %d %b %Y
+datetimeformat     = %d %b %H:%M
+longdatetimeformat = %d %b %Y %H:%M
+weeknumbers        = left
+
+[keybindings]
+external_edit = ctrl e
+
+[view]
+# agenda_event_format   = {calendar-color}{cancelled}{start-end-time-style} {title}{repeat-symbol} {location} {reset}
+agenda_event_format   = {calendar-color}{cancelled}{start-end-time-style} {title}{repeat-symbol} {location} {url}{reset}
+event_format          = {calendar-color}{cancelled}{start}-{end} {title}{repeat-symbol} {location} {url}{reset}
+blank_line_before_day = true
diff --git a/home/default.nix b/home/default.nix
index f587184..da72d47 100644
--- a/home/default.nix
+++ b/home/default.nix
@@ -60,8 +60,8 @@
     urlscan
 
     # office
-    vdirsyncer
     khal
+    # vdirsyncer
     khard
     taskopen
     gnome.gnome-sound-recorder
@@ -105,14 +105,15 @@
   ];
 
   imports = [
-    ./R.nix
+    ./desktop
     ./nvim
     ./foot.nix
     ./fish.nix
+    ./calendars
     ./mail
     ./tex.nix
     ./openconnect.nix
-    ./desktop
+    ./R.nix
   ];
 
   home.shellAliases = {
diff --git a/home/tex.nix b/home/tex.nix
index 09dedf0..342294a 100644
--- a/home/tex.nix
+++ b/home/tex.nix
@@ -12,6 +12,7 @@ let
       environ
       framed
       gensymb
+      graphbox
       lastpage
       lipsum
       ly1
diff --git a/system/btrbk.nix b/system/btrbk.nix
index 8fe7cc5..c8e7277 100644
--- a/system/btrbk.nix
+++ b/system/btrbk.nix
@@ -10,8 +10,8 @@
         snapshot_preserve = "40d";
         snapshot_preserve_min = "4d";
         snapshot_dir = "/btrbk_snapshots";
-        target = "/run/media/till/backup";
-        target_preserve_min = "no";
+        target = "/run/media/till/backup/${config.networking.hostName}";
+        target_preserve_min = "2h";
         target_preserve = "40d 52w *m";
       };
     };