diff -Naur 4th-3.64.0-old/sources/Makefile 4th-3.64.0-new/sources/Makefile
--- 4th-3.64.0-old/sources/Makefile	2022-03-15 12:37:45.925122854 -0300
+++ 4th-3.64.0-new/sources/Makefile	2022-03-15 12:38:50.987870211 -0300
@@ -125,7 +125,7 @@
 
 install: mostlyinstall
 	install -Dm644 ../documentation/4th.1 $(MANDIR)/man1/4th.1
-	install -Dm644 ../documentation/4tHmanual.txt $(DOCDIR)/4th/
+	install -Dm644 ../documentation/4tHmanual.pdf $(DOCDIR)/4th/
 
 uninstall:
 	-rm -f $(LIBRARIES)/lib4th.{a,so*}