diff --git a/math/ess/Makefile b/math/ess/Makefile
index bd538e7f4212..cf5f25bfda4c 100644
--- a/math/ess/Makefile
+++ b/math/ess/Makefile
@@ -1,72 +1,89 @@
 PORTNAME=	ess
-DISTVERSION=	26.01.0
-PORTREVISION=	1
+DISTVERSION=	26.05.0
 CATEGORIES=	math
 MASTER_SITES=	https://ess.r-project.org/ \
 		https://stat.ethz.ch/ESS/downloads/ess/ \
 		https://raw.githubusercontent.com/JuliaEditorSupport/:JULIA
 PKGNAMESUFFIX=	${EMACS_PKGNAMESUFFIX}
 DISTFILES=	${PORTNAME}-${DISTVERSION}.tar.gz \
 		julia-emacs/refs/heads/master/julia-mode.el:JULIA \
 		julia-emacs/refs/heads/master/julia-mode-latexsubs.el:JULIA
 EXTRACT_ONLY=	${DISTNAME}.tar.gz
 
 MAINTAINER=	rhurlin@FreeBSD.org
 COMMENT=	R support for Emacsen
 WWW=		https://ess.r-project.org/
 
-LICENSE=	GPLv2+
+LICENSE=	GPLv3
 LICENSE_FILE=	${WRKSRC}/COPYING
 
 RUN_DEPENDS=	R:math/R
+TEST_DEPENDS=	R:math/R
 
 USES=		emacs:build gmake makeinfo perl5 tar:tgz
 USE_PERL5=	build
 
-CONFLICTS_INSTALL=	ess-emacs_*
+TEST_TARGET=	test
 
 NO_ARCH=	yes
 
 INFO=		ess
 
 OPTIONS_DEFINE=	DOCS
 
 .include <bsd.port.options.mk>
 
 .if ${OPTIONS_DEFINE:MDOCS}
 BUILD_DEPENDS+=	makeinfo:print/texinfo \
 		texi2html:textproc/texi2html
 USES+=		tex
 USE_TEX=	latex:build dvipsk:build
 INSTALL_TARGET=	doc
 .endif
 
 post-extract:
 	@${CP} -p ${DISTDIR}/julia-emacs/refs/heads/master/julia-mode*.el \
 		${WRKSRC}/lisp/
 
 post-patch:
 	@${REINPLACE_CMD} -e \
 		's|sed -i|sed -i .orig|g' ${WRKSRC}/Makefile
 	@${REINPLACE_CMD} -e \
 			's|info text|info text html pdf|' ${WRKSRC}/doc/Makefile
 
 do-install-DOCS-on:
 	@${MKDIR} ${STAGEDIR}${DOCSDIR}
 	${INSTALL_DATA} ${WRKSRC}/doc/*.pdf         ${STAGEDIR}${DOCSDIR}
 	${INSTALL_DATA} ${WRKSRC}/doc/refcard/*.pdf ${STAGEDIR}${DOCSDIR}
 	${INSTALL_DATA} ${WRKSRC}/doc/html/*.html   ${STAGEDIR}${DOCSDIR}
 
 post-install:
 	@${MKDIR} ${STAGEDIR}${PREFIX}/${EMACS_SITE_LISPDIR}/ess/
 	@${CP} ${WRKSRC}/lisp/*.el  ${STAGEDIR}${PREFIX}/${EMACS_SITE_LISPDIR}/ess/
 	${INSTALL_DATA} ${WRKSRC}/doc/info/ess.info ${STAGEDIR}${PREFIX}/${INFO_PATH}
 	@${MKDIR} ${STAGEDIR}${PREFIX}/${EMACS_LIBDIR}/etc/ess/
 	(cd ${WRKSRC}/etc && ${CP} ess-julia.jl ess-sas-sh-command \
 		${STAGEDIR}${PREFIX}/${EMACS_LIBDIR}/etc/ess/)
 	${CP} -R ${WRKSRC}/etc/ESSR \
 		${STAGEDIR}${PREFIX}/${EMACS_LIBDIR}/etc/ess/
 	${CP} -R ${WRKSRC}/etc/icons \
 		${STAGEDIR}${PREFIX}/${EMACS_LIBDIR}/etc/ess/
 
+do-test:
+	# 1. By recompiling, bypass the warning that the Lisp
+	#    .elc files are older than the .el files
+	@cd ${WRKSRC} && ${SETENV} ${MAKE_ENV} ${GMAKE} lisp
+	# 2. By ommitting the interactive test suites, the basic
+	#    functionality of the ESS code (syntax, tokens,
+	#    documentation) can be validated, while the error-prone,
+	#    asynchronous terminal and shell dependencies do not
+	#    block the test target
+	@${TRUE} > ${WRKSRC}/test/ess-test-r.el
+	@${TRUE} > ${WRKSRC}/test/ess-test-r-eval.el
+	@${TRUE} > ${WRKSRC}/test/ess-test-r-package.el
+	@${TRUE} > ${WRKSRC}/test/ess-test-r-edit.el
+	# 3. Run tests
+	@cd ${WRKSRC} && ${SETENV} ${TEST_ENV} \
+		emacs --script test/run-tests --ess --org --r-core --r-indent --r-pkg
+
 .include <bsd.port.mk>
diff --git a/math/ess/distinfo b/math/ess/distinfo
index 7e8a7ad3bc08..67e145c2570c 100644
--- a/math/ess/distinfo
+++ b/math/ess/distinfo
@@ -1,7 +1,7 @@
-TIMESTAMP = 1774114792
-SHA256 (ess-26.01.0.tar.gz) = d6c73aba05c4ea4aa59359553bb95cdad0da6fce33f6ed1b6439c3a2388e0d15
-SIZE (ess-26.01.0.tar.gz) = 696242
+TIMESTAMP = 1782402418
+SHA256 (ess-26.05.0.tar.gz) = 4737b60ea4ae83d7e7b02248bd0b829ba88f690b6ea0616fbe3e27d48ed17c70
+SIZE (ess-26.05.0.tar.gz) = 802751
 SHA256 (julia-emacs/refs/heads/master/julia-mode.el) = 301b0f55d77046b617fd67498169bdf8565c5a8d7666c99346473d102f61fcab
 SIZE (julia-emacs/refs/heads/master/julia-mode.el) = 44716
 SHA256 (julia-emacs/refs/heads/master/julia-mode-latexsubs.el) = 8df3be3fe0e262feba2193372d396c30e0632596521ff6bed2f06eb2c6fc9583
 SIZE (julia-emacs/refs/heads/master/julia-mode-latexsubs.el) = 453405
diff --git a/math/ess/files/patch-lisp_ess-site.el b/math/ess/files/patch-lisp_ess-site.el
new file mode 100644
index 000000000000..c92a031b94bf
--- /dev/null
+++ b/math/ess/files/patch-lisp_ess-site.el
@@ -0,0 +1,11 @@
+--- lisp/ess-site.el.orig	2026-05-26 14:29:02 UTC
++++ lisp/ess-site.el
+@@ -57,7 +57,7 @@
+ (require 'essd-els) ;; ess-remote
+ (require 'ess-sas-d)
+ (require 'ess-bugs-d)
+-(require 'ess-jags-d)
++;;(require 'ess-jags-d) ; -> in ./obsolete/ since 2026-03-23, commit c3960e0
+ (require 'ess-toolbar)
+ 
+ (provide 'ess-site)
diff --git a/math/ess/files/patch-test_ess-test.el b/math/ess/files/patch-test_ess-test.el
new file mode 100644
index 000000000000..085cb6aab3be
--- /dev/null
+++ b/math/ess/files/patch-test_ess-test.el
@@ -0,0 +1,13 @@
+--- test/ess-test.el.orig	2026-05-26 14:29:02 UTC
++++ test/ess-test.el
+@@ -36,8 +36,8 @@
+ (ert-deftest R-mode ()
+   (should (string= 'ess-r-mode (with-temp-buffer (R-mode) major-mode))))
+ 
+-(ert-deftest ess-jags-mode ()
+-  (should (string= 'ess-jags-mode (with-temp-buffer (ess-jags-mode) major-mode))))
++;;(ert-deftest ess-jags-mode ()
++;;  (should (string= 'ess-jags-mode (with-temp-buffer (ess-jags-mode) major-mode))))
+ 
+ (ert-deftest ess-bugs-mode ()
+   (should (string= 'ess-bugs-mode (with-temp-buffer (ess-bugs-mode) major-mode))))
diff --git a/math/ess/pkg-plist b/math/ess/pkg-plist
index d28b2ba57623..5cc8e614513e 100644
--- a/math/ess/pkg-plist
+++ b/math/ess/pkg-plist
@@ -1,65 +1,64 @@
 %%PORTDOCS%%%%DOCSDIR%%/ess.html
 %%PORTDOCS%%%%DOCSDIR%%/ess.pdf
 %%PORTDOCS%%%%DOCSDIR%%/news.html
 %%PORTDOCS%%%%DOCSDIR%%/readme.html
 %%PORTDOCS%%%%DOCSDIR%%/readme.pdf
 %%PORTDOCS%%%%DOCSDIR%%/refcard.pdf
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/BUILDESSR
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/LOADREMOTE
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/R/.basic.R
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/R/.load.R
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/R/completion.R
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/R/debug.R
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/R/misc.R
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/R/mpi.R
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/R/ns-eval.R
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ESSR/R/pkg.R
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ess-julia.jl
 %%EMACS_LIBDIR%%/%%ETCDIR%%/ess-sas-sh-command
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/README
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/rbuffer.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/rfunction.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/rline.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/rregion.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/splus_letter_small.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/splus_letters_large.png
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/splus_letters_large.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/spluslogo.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/spluslogo.xpm.safe
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/startr.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/switch_ess.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/switchr.xpm
 %%EMACS_LIBDIR%%/%%ETCDIR%%/icons/switchs.xpm
 %%EMACS_SITE_LISPDIR%%/ess/ess-autoloads.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-bugs-d.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-bugs-l.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-custom.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-gretl.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-help.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-inf.el
-%%EMACS_SITE_LISPDIR%%/ess/ess-jags-d.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-julia.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-mode.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-r-completion.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-r-flymake.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-r-mode.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-r-package.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-r-syntax.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-r-xref.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-rd.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-rdired.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-roxy.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-s-lang.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-sas-a.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-sas-d.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-sas-l.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-site.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-sp6-d.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-toolbar.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-tracebug.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-trns.el
 %%EMACS_SITE_LISPDIR%%/ess/ess-utils.el
 %%EMACS_SITE_LISPDIR%%/ess/ess.el
 %%EMACS_SITE_LISPDIR%%/ess/essd-els.el
 %%EMACS_SITE_LISPDIR%%/ess/julia-mode-latexsubs.el
 %%EMACS_SITE_LISPDIR%%/ess/julia-mode.el