diff --git a/net/unison/2.4x/Makefile b/net/unison/2.4x/Makefile
index 079a9b8e989..dd87b00ff36 100644
--- a/net/unison/2.4x/Makefile
+++ b/net/unison/2.4x/Makefile
@@ -1,8 +1,8 @@
-# $OpenBSD: Makefile,v 1.11 2020/11/05 05:35:33 bket Exp $
+# $OpenBSD: Makefile,v 1.12 2021/01/03 19:59:15 bket Exp $
 
 VER=		2.48.15
 REV=		v4
-REVISION=	4
+REVISION=	5
 GH_TAGNAME=	v${VER}${REV}
 PKGNAME=	unison-${VER}${REV:S/^v/pl/}
 
diff --git a/net/unison/2.4x/pkg/README b/net/unison/2.4x/pkg/README
index 81e50dfd8cb..67a03c66ae1 100644
--- a/net/unison/2.4x/pkg/README
+++ b/net/unison/2.4x/pkg/README
@@ -1,4 +1,4 @@
-$OpenBSD: README,v 1.4 2019/09/22 18:29:54 chrisz Exp $
+$OpenBSD: README,v 1.5 2021/01/03 19:59:15 bket Exp $
 
 +-----------------------------------------------------------------------
 | Running ${PKGSTEM} on OpenBSD
@@ -6,13 +6,24 @@ $OpenBSD: README,v 1.4 2019/09/22 18:29:54 chrisz Exp $
 
 Unison uses native OCaml marshalling in its prococol. This
 means that unison might not work when the OCaml versions of
-two instances are out of sync.
-One way to work around this limitation of unison is to use
+two instances are out of sync. Assuming that both ends are
+OpenBSD and under control by the user, pkg_add(1) can be used
+to sync unison and ocaml.
+
+Another way to work around this limitation of unison is to use
 the OPAM OCaml package manager to build unison with the same
 version of the OCaml compiler on all machines:
 
 doas pkg_add opam
-OPAMROOT=~/opam_unison
+export OPAMROOT=~/opam_unison
 opam init --no-setup --compiler ocaml-base-compiler.4.09.0
 opam install unison lablgtk  # To build without the gui, remove lablgtk
 $(opam var bin)/unison
+
+Common issue
+=============
+Unison sometimes reports chown() failures that are actually
+failures to change group ownership. This can occur when a user
+does not belong to the specified group and is the owner of the
+file, or is not the superuser. Issue can be addressed by setting
+the option 'group' to 'false'.
diff --git a/net/unison/2.5x/Makefile b/net/unison/2.5x/Makefile
index 8eca993c137..c77616ea4f1 100644
--- a/net/unison/2.5x/Makefile
+++ b/net/unison/2.5x/Makefile
@@ -1,5 +1,6 @@
-# $OpenBSD: Makefile,v 1.9 2020/11/03 19:45:30 bket Exp $
+# $OpenBSD: Makefile,v 1.10 2021/01/03 19:59:15 bket Exp $
 
 GH_TAGNAME=	v2.51.3
+REVISION=	0
 
 .include <bsd.port.mk>
diff --git a/net/unison/2.5x/pkg/README b/net/unison/2.5x/pkg/README
index 81e50dfd8cb..67a03c66ae1 100644
--- a/net/unison/2.5x/pkg/README
+++ b/net/unison/2.5x/pkg/README
@@ -1,4 +1,4 @@
-$OpenBSD: README,v 1.4 2019/09/22 18:29:54 chrisz Exp $
+$OpenBSD: README,v 1.5 2021/01/03 19:59:15 bket Exp $
 
 +-----------------------------------------------------------------------
 | Running ${PKGSTEM} on OpenBSD
@@ -6,13 +6,24 @@ $OpenBSD: README,v 1.4 2019/09/22 18:29:54 chrisz Exp $
 
 Unison uses native OCaml marshalling in its prococol. This
 means that unison might not work when the OCaml versions of
-two instances are out of sync.
-One way to work around this limitation of unison is to use
+two instances are out of sync. Assuming that both ends are
+OpenBSD and under control by the user, pkg_add(1) can be used
+to sync unison and ocaml.
+
+Another way to work around this limitation of unison is to use
 the OPAM OCaml package manager to build unison with the same
 version of the OCaml compiler on all machines:
 
 doas pkg_add opam
-OPAMROOT=~/opam_unison
+export OPAMROOT=~/opam_unison
 opam init --no-setup --compiler ocaml-base-compiler.4.09.0
 opam install unison lablgtk  # To build without the gui, remove lablgtk
 $(opam var bin)/unison
+
+Common issue
+=============
+Unison sometimes reports chown() failures that are actually
+failures to change group ownership. This can occur when a user
+does not belong to the specified group and is the owner of the
+file, or is not the superuser. Issue can be addressed by setting
+the option 'group' to 'false'.