diff --git a/math/maxima/Makefile b/math/maxima/Makefile
index 7ce0147bd919..317a55de8a32 100644
--- a/math/maxima/Makefile
+++ b/math/maxima/Makefile
@@ -6,8 +6,7 @@
 #
 
 PORTNAME=	maxima
-PORTVERSION=	5.27.0
-PORTREVISION=	3
+PORTVERSION=	5.28.0
 CATEGORIES=	math lisp tk
 MASTER_SITES=	SF/maxima/Maxima-source/${PORTVERSION}-source
 
@@ -40,7 +39,7 @@ PLIST_SUB+=	LISPBIN=${LISPBINARY}
 PLIST_SUB+=	MAXIMABIN=${MAXIMABINARY}
 PLIST_SUB+=	PORTVERSION=${PORTVERSION}
 
-OPTIONS_SINGLE=	LISP
+OPTIONS_SINGLE=		LISP
 OPTIONS_SINGLE_LISP=	CLISP CMUCL GCL SBCL
 
 OPTIONS_DEFAULT=	SBCL
@@ -115,6 +114,8 @@ post-patch:
 .if defined(MAXIMA_LISP_OPTIONS) && !empty(MAXIMA_LISP_OPTIONS)
 	@${REINPLACE_CMD} -e 's;"@SBCL_NAME@";@SBCL_NAME@;g' \
 	${WRKSRC}/src/maxima.in
+	@${REINPLACE_CMD} -e 's;"$$(SBCL_NAME)";$$(SBCL_NAME);g' \
+	${WRKSRC}/src/Makefile.in
 .endif
 
 pre-build:
diff --git a/math/maxima/distinfo b/math/maxima/distinfo
index 7c61a2409be9..af289c113aaf 100644
--- a/math/maxima/distinfo
+++ b/math/maxima/distinfo
@@ -1,2 +1,2 @@
-SHA256 (maxima-5.27.0.tar.gz) = 9006803714f1385221c4395697fad53f125a13d29b50b188d045d08e25f8dca7
-SIZE (maxima-5.27.0.tar.gz) = 27101764
+SHA256 (maxima-5.28.0.tar.gz) = d73e925f0116ba361bf4390c80e24d4fa763f647cc1fc4cc06bbf40ceb3facda
+SIZE (maxima-5.28.0.tar.gz) = 27312348
diff --git a/math/maxima/pkg-message b/math/maxima/pkg-message
index ac35095ac1a2..0f36b5e22b49 100644
--- a/math/maxima/pkg-message
+++ b/math/maxima/pkg-message
@@ -1,5 +1,5 @@
-When built with sbcl, maxima imposes a default memory limit of 512MiB on i386,
-and 1GiB on amd64.  The limit can be changed by defining DYNAMIC_SPACE_SIZE
+When built with sbcl, maxima imposes a default memory limit of 512 MiB on i386,
+and 1 GiB on amd64.  The limit can be changed by defining DYNAMIC_SPACE_SIZE
 in the build environment.  The limit can be overridden later, at run-time,
 via the -X or --lisp-options options, or by defining the environment variable
 MAXIMA_LISP_OPTIONS.
diff --git a/math/maxima/pkg-plist b/math/maxima/pkg-plist
index d2ab79cf5eb2..f6f4d63a3c41 100644
--- a/math/maxima/pkg-plist
+++ b/math/maxima/pkg-plist
@@ -424,6 +424,7 @@ libexec/maxima/%%PORTVERSION%%/mgnuplot
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/Zeilberger/zeilberger.mac
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/Zeilberger/zeilberger_algorithm.mac
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/Zeilberger/zeilberger_linear_algebra.mac
+%%DATADIR%%/%%PORTVERSION%%/share/contrib/aes.mac
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/altsimp/altsimp.lisp
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/augmented_lagrangian.mac
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/bitwise/bitwise.lisp
@@ -522,11 +523,11 @@ libexec/maxima/%%PORTVERSION%%/mgnuplot
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/fresnel/readme.txt
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/convmac.lisp
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/fdata.lisp
+%%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/gentran.lisp
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/global.lisp
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/gtfix.lisp
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/init.lisp
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/intrfc.lisp
-%%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/local.gtload.lisp
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/lspc.lisp
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/lspfor.lisp
 %%DATADIR%%/%%PORTVERSION%%/share/contrib/gentran/lsprat.lisp
@@ -1486,7 +1487,6 @@ libexec/maxima/%%PORTVERSION%%/mgnuplot
 %%DATADIR%%/%%PORTVERSION%%/src/intpol.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/invert.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/irinte.lisp
-%%DATADIR%%/%%PORTVERSION%%/src/kclmac.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/laplac.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/ldisp.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/lesfac.lisp
@@ -1683,7 +1683,6 @@ libexec/maxima/%%PORTVERSION%%/mgnuplot
 %%DATADIR%%/%%PORTVERSION%%/src/rat3e.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/ratmac.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/ratout.lisp
-%%DATADIR%%/%%PORTVERSION%%/src/ratpoi.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/residu.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/result.lisp
 %%DATADIR%%/%%PORTVERSION%%/src/risch.lisp