diff --git a/ebook/__init__.py b/ebook/__init__.py
index ea15ff5..a9f40ee 100644
--- a/ebook/__init__.py
+++ b/ebook/__init__.py
@@ -63,14 +63,14 @@ frontmatter_template = '''<?xml version="1.0" encoding="UTF-8" standalone="no"?>
 
 @attr.s
 class CoverOptions:
-    fontname = attr.ib(default=None, convert=attr.converters.optional(str))
-    fontsize = attr.ib(default=None, convert=attr.converters.optional(int))
-    width = attr.ib(default=None, convert=attr.converters.optional(int))
-    height = attr.ib(default=None, convert=attr.converters.optional(int))
-    wrapat = attr.ib(default=None, convert=attr.converters.optional(int))
-    bgcolor = attr.ib(default=None, convert=attr.converters.optional(tuple))
-    textcolor = attr.ib(default=None, convert=attr.converters.optional(tuple))
-    cover_url = attr.ib(default=None, convert=attr.converters.optional(str))
+    fontname = attr.ib(default=None, converter=attr.converters.optional(str))
+    fontsize = attr.ib(default=None, converter=attr.converters.optional(int))
+    width = attr.ib(default=None, converter=attr.converters.optional(int))
+    height = attr.ib(default=None, converter=attr.converters.optional(int))
+    wrapat = attr.ib(default=None, converter=attr.converters.optional(int))
+    bgcolor = attr.ib(default=None, converter=attr.converters.optional(tuple))
+    textcolor = attr.ib(default=None, converter=attr.converters.optional(tuple))
+    cover_url = attr.ib(default=None, converter=attr.converters.optional(str))
 
 
 def chapter_html(story, titleprefix=None):
diff --git a/requirements.txt b/requirements.txt
index ffa6aac..d14ed35 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,10 +1,10 @@
 astroid==2.2.5
-attrs==19.1.0
-beautifulsoup4==4.7.1
+attrs==19.2.0
+beautifulsoup4==4.8.1
 certifi==2017.7.27.1
 chardet==3.0.4
 Click==7.0
-click-default-group==1.2
+click-default-group==1.2.2
 entrypoints==0.3
 flake8==3.7.7
 html5lib==1.0.1
@@ -13,15 +13,15 @@ isort==4.3.17
 lazy-object-proxy==1.3.1
 mccabe==0.6.1
 olefile==0.44
-Pillow==6.0.0
+Pillow==6.2.0
 pycodestyle==2.5.0
 pyflakes==2.1.1
 pylint==2.3.1
 requests==2.22.0
-requests-cache==0.5.0
+requests-cache==0.5.2
 six==1.10.0
 soupsieve==1.9.1
 typed-ast==1.3.4
-urllib3==1.25.3
+urllib3==1.25.6
 webencodings==0.5.1
 wrapt==1.11.1
diff --git a/sites/__init__.py b/sites/__init__.py
index 095a1ff..6ec9c87 100644
--- a/sites/__init__.py
+++ b/sites/__init__.py
@@ -23,7 +23,7 @@ class Chapter:
     title = attr.ib()
     contents = attr.ib()
     date = attr.ib(default=False)
-    id = attr.ib(default=attr.Factory(_default_uuid_string), convert=str)
+    id = attr.ib(default=attr.Factory(_default_uuid_string), converter=str)
 
 
 @attr.s
@@ -32,7 +32,7 @@ class Section:
     author = attr.ib()
     url = attr.ib()
     cover_url = attr.ib(default='')
-    id = attr.ib(default=attr.Factory(_default_uuid_string), convert=str)
+    id = attr.ib(default=attr.Factory(_default_uuid_string), converter=str)
     contents = attr.ib(default=attr.Factory(list))
     footnotes = attr.ib(default=attr.Factory(list))
     summary = attr.ib(default='')