diff --git a/base b/base
index bd97e1b3a..9ae3c3627 160000
--- a/base
+++ b/base
@@ -1 +1 @@
-Subproject commit bd97e1b3ab7184d383c87237ec8dd8f02bac0301
+Subproject commit 9ae3c362787d58f8fa990771f243388a7aa8ac03
diff --git a/frontend/document/pdfdocument.lua b/frontend/document/pdfdocument.lua
index a80b7048d..146f2aef7 100644
--- a/frontend/document/pdfdocument.lua
+++ b/frontend/document/pdfdocument.lua
@@ -239,6 +239,7 @@ end
 function PdfDocument:register(registry)
     registry:addProvider("pdf", "application/pdf", self)
     registry:addProvider("cbz", "application/cbz", self)
+    registry:addProvider("cbt", "application/cbt", self)
     registry:addProvider("zip", "application/zip", self)
     registry:addProvider("xps", "application/xps", self)
 end