diff --git a/.gitignore b/.gitignore
index 6e4a9e6..91d5d6f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,4 +9,3 @@ advancecomp-1.15.tar.gz
 /advancecomp-2.3.tar.gz
 /advancecomp-2.4.tar.gz
 /advancecomp-2.5.tar.gz
-/advancecomp-2.6.tar.gz
diff --git a/advancecomp.rpmlintrc b/advancecomp.rpmlintrc
index 4e393f3..f783f4d 100644
--- a/advancecomp.rpmlintrc
+++ b/advancecomp.rpmlintrc
@@ -1,6 +1,4 @@
-# Not real spelling errors
-addFilter(r" spelling-error \('[Rr]ecompression',")
-addFilter(r" spelling-error \('([pm]ng|gz)',")
-addFilter(r" spelling-error \('adv(zip|[pm]ng|def)',")
-# Intentional, with a justifying spec-file comment
-addFilter(r" no-%check-section")
+# There is really no version information available.
+addFilter(r' unversioned-explicit-provides bundled\(7zip\)')
+# Every RPM has this…
+addFilter(r' strange-permission advancecomp\.spec 600$')
diff --git a/advancecomp.spec b/advancecomp.spec
index 3c193c4..246bda8 100644
--- a/advancecomp.spec
+++ b/advancecomp.spec
@@ -1,5 +1,5 @@
 Name:           advancecomp
-Version:        2.6
+Version:        2.5
 Release:        %autorelease
 Summary:        Recompression utilities for .png, .mng, .zip and .gz files
 
@@ -14,18 +14,13 @@ Summary:        Recompression utilities for .png, .mng, .zip and .gz files
 #   of the sources that would be covered by the “unRAR license restriction” or
 #   the BSD-3-Clause license for LZFSE are present in this fork.
 #
+#   Certain build-system files, which do not contribute to the license of the
+#   binary RPM, are under other permissible licenses.
+#
 # However, in version 1.17, the COPYING file was updated to GPLv3, with a
 # changelog message (in HISTORY and elsewhere) of “Changes to GPL3.” We
 # interpret this as an overall license of GPL-3.0-only.
 License:        GPL-3.0-only AND GPL-2.0-or-later AND LGPL-2.1-or-later
-# Additionally, the following bundled libraries are removed in %%prep and do
-# not contribute to the licenses of the binary RPMs:
-#
-# Apache-2.0:
-#   - zopfli/
-# MIT:
-#   - libdeflate/
-SourceLicense:  %{license} AND Apache-2.0 AND MIT
 URL:            https://www.advancemame.it/
 %global forgeurl https://github.com/amadvance/advancecomp
 Source:         %{forgeurl}/archive/v%{version}/advancecomp-%{version}.tar.gz
@@ -43,13 +38,9 @@ BuildRequires:  dos2unix
 BuildRequires:  zlib-devel
 
 # Unbundled downstream
-BuildRequires:  pkgconfig(libdeflate) >= 1.19
+BuildRequires:  pkgconfig(libdeflate)
 BuildRequires:  zopfli-devel
 
-# The point of the 2.6 release was to upgrade the bundled libdeflate; enforce
-# this on the unbundled libdeflate.
-Requires:       libdeflate >= 1.19
-
 # From 7z/README:
 #
 #   This directory contains some source files from the
@@ -89,7 +80,7 @@ This package contains:
 dos2unix -k doc/*.txt
 
 # Patch out bundled libdeflate
-rm -rv libdeflate
+rm -rvf libdeflate
 sed -r -i '/libdeflate[\/_]/d' Makefile.am
 # Fix up #include paths. The find-then-modify pattern keeps us from discarding
 # mtimes on any sources that do not need modification.
@@ -99,7 +90,7 @@ find . -type f -exec gawk \
   xargs -r -t sed -r -i 's@^([[:blank:]]*#include.*)libdeflate/@\1@'
 
 # Patch out bundled zopfli
-rm -rv zopfli
+rm -rvf zopfli
 sed -r -i \
     -e '/zopfli[\/_]/d' \
     -e 's/((\(7z_SOURCES\)|WindowOut\.h).*)[[:blank:]]*\\/\1/' \
@@ -112,7 +103,7 @@ find . -type f -exec gawk \
   xargs -r -t sed -r -i -e 's@^([[:blank:]]*#include.*)zopfli/@\1@'
 
 
-%conf
+%build
 autoreconf --force --install --verbose
 
 # Link against system libdeflate
@@ -124,9 +115,6 @@ export LDFLAGS="$(pkgconf --libs libdeflate) ${LDFLAGS-}"
 export LDFLAGS="-lzopfli ${LDFLAGS-}"
 
 %configure
-
-
-%build
 %make_build
 
 
diff --git a/sources b/sources
index a8812ed..04420d1 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-SHA512 (advancecomp-2.6.tar.gz) = 63cbb0578f96fd3f55ccb49e31bfe945649d36a11558aa482332440943d6d347f161de797b8d4469562b1d551b274c22fe08818179926d56aa4746581d3926dd
+SHA512 (advancecomp-2.5.tar.gz) = c508526415dc002dad442e3f55202494ab2c49ecac3f5ea6e1a3fe27d224dd9a1a33dace02f59c18123d3f4bc74e3f03556b1cff6541cb88dcaaa32ac35c0043