diff --git a/crates/core/src/document/mupdf_sys.rs b/crates/core/src/document/mupdf_sys.rs
index 5b4179e..90424cc 100644
--- a/crates/core/src/document/mupdf_sys.rs
+++ b/crates/core/src/document/mupdf_sys.rs
@@ -3,7 +3,7 @@
 use std::mem;
 
 pub const FZ_MAX_COLORS: usize = 32;
-pub const FZ_VERSION: &str = "1.22.2";
+pub const FZ_VERSION: &str = "1.23.5";
 
 pub const FZ_META_INFO_AUTHOR: &str = "info:Author";
 pub const FZ_META_INFO_TITLE: &str = "info:Title";
diff --git a/doc/BUILD.md b/doc/BUILD.md
index 1cdf2c9..4aaa703 100644
--- a/doc/BUILD.md
+++ b/doc/BUILD.md
@@ -39,7 +39,7 @@ rustup target add arm-unknown-linux-gnueabihf
 
 ## Developer Tools
 
-Install the required dependencies: *MuPDF 1.22.2*, *DjVuLibre*, *FreeType*, *HarfBuzz*.
+Install the required dependencies: *MuPDF 1.23.5*, *DjVuLibre*, *FreeType*, *HarfBuzz*.
 
 ### Emulator
 
diff --git a/thirdparty/download.sh b/thirdparty/download.sh
index 0fa3054..9260205 100755
--- a/thirdparty/download.sh
+++ b/thirdparty/download.sh
@@ -2,7 +2,7 @@
 
 declare -A urls=(
 	# Compression
-	["zlib"]="https://zlib.net/zlib-1.2.13.tar.gz"
+	["zlib"]="https://www.zlib.net/zlib-1.3.tar.gz"
 	["bzip2"]="https://sourceware.org/pub/bzip2/bzip2-1.0.8.tar.gz"
 	# Images
 	["libpng"]="https://download.sourceforge.net/libpng/libpng-1.6.40.tar.gz"
@@ -10,12 +10,12 @@ declare -A urls=(
 	["openjpeg"]="https://github.com/uclouvain/openjpeg/archive/v2.5.0.tar.gz"
 	["jbig2dec"]="https://github.com/ArtifexSoftware/ghostpdl-downloads/releases/download/gs9533/jbig2dec-0.19.tar.gz"
 	# Fonts
-	["freetype2"]="https://download.savannah.gnu.org/releases/freetype/freetype-2.13.1.tar.gz"
+	["freetype2"]="https://download.savannah.gnu.org/releases/freetype/freetype-2.13.2.tar.gz"
 	["harfbuzz"]="https://github.com/harfbuzz/harfbuzz/archive/3.0.0.tar.gz" # We're stuck at 3.0.0.
 	# Documents
 	["gumbo"]="https://github.com/google/gumbo-parser/archive/v0.10.1.tar.gz"
 	["djvulibre"]="http://downloads.sourceforge.net/djvu/djvulibre-3.5.28.tar.gz"
-	["mupdf"]="https://mupdf.com/downloads/archive/mupdf-1.22.2-source.tar.gz"
+	["mupdf"]="https://mupdf.com/downloads/archive/mupdf-1.23.5-source.tar.gz"
 )
 
 for name in "${@:-${!urls[@]}}" ; do
diff --git a/thirdparty/mupdf/kobo.patch b/thirdparty/mupdf/kobo.patch
index 9360c33..844db00 100644
--- a/thirdparty/mupdf/kobo.patch
+++ b/thirdparty/mupdf/kobo.patch
@@ -1,6 +1,6 @@
 diff -ru a/Makefile b/Makefile
---- a/Makefile	2023-04-13 14:30:09
-+++ b/Makefile	2023-04-17 09:46:46
+--- a/Makefile	2023-11-14 09:46:57
++++ b/Makefile	2023-11-14 09:47:11
 @@ -150,7 +150,7 @@
  
  THIRD_GLUT_OBJ := $(THIRD_GLUT_SRC:%.c=$(OUT)/%.o)
@@ -11,9 +11,9 @@ diff -ru a/Makefile b/Makefile
  MUPDF_SRC += $(sort $(wildcard source/pdf/*.c))
  MUPDF_SRC += $(sort $(wildcard source/xps/*.c))
 diff -ru a/Makerules b/Makerules
---- a/Makerules	2023-04-13 14:30:09
-+++ b/Makerules	2023-04-17 09:47:24
-@@ -300,6 +300,35 @@
+--- a/Makerules	2023-11-14 09:46:58
++++ b/Makerules	2023-11-14 09:47:11
+@@ -321,6 +321,35 @@
    HAVE_WIN32=yes
  endif
  
@@ -50,8 +50,8 @@ diff -ru a/Makerules b/Makerules
  # which is called from the Xcode project as a "Run Script" build step.
  # The following section works for both device and simulator builds.
 diff -ru a/Makethird b/Makethird
---- a/Makethird	2023-04-13 14:30:09
-+++ b/Makethird	2023-04-17 09:48:23
+--- a/Makethird	2023-11-14 09:46:58
++++ b/Makethird	2023-11-14 09:47:11
 @@ -43,10 +43,6 @@
    endif
  endif
@@ -100,3 +100,27 @@ diff -ru a/Makethird b/Makethird
 -	@touch $@
 -
 -generate: thirdparty/extract/src/docx_template.c
+diff -ru a/source/html/html-parse.c b/source/html/html-parse.c
+--- a/source/html/html-parse.c	2023-11-14 09:46:58
++++ b/source/html/html-parse.c	2023-11-14 09:59:43
+@@ -1622,13 +1622,13 @@
+ }
+ 
+ static const char *mobi_font_size[7] = {
+-	"8pt",
+-	"10pt",
+-	"12pt",
+-	"14pt",
+-	"16pt",
+-	"18pt",
+-	"20pt",
++	"0.67em",
++	"0.83em",
++	"1em",
++	"1.17em",
++	"1.33em",
++	"1.5em",
++	"1.67em",
+ };
+ 
+ static void