diff --git a/pkgs/development/libraries/exiv2/default.nix b/pkgs/development/libraries/exiv2/default.nix
index 9d29afd6927..930bfc99f28 100644
--- a/pkgs/development/libraries/exiv2/default.nix
+++ b/pkgs/development/libraries/exiv2/default.nix
@@ -1,6 +1,5 @@
 { lib, stdenv
 , fetchFromGitHub
-, fetchpatch
 , zlib
 , expat
 , cmake
@@ -11,11 +10,12 @@
 , doxygen
 , graphviz
 , libxslt
+, libiconv
 }:
 
 stdenv.mkDerivation rec {
   pname = "exiv2";
-  version = "0.27.3";
+  version = "0.27.4";
 
   outputs = [ "out" "dev" "doc" "man" ];
 
@@ -23,30 +23,9 @@ stdenv.mkDerivation rec {
     owner = "exiv2";
     repo  = "exiv2";
     rev = "v${version}";
-    sha256 = "0d294yhcdw8ziybyd4rp5hzwknzik2sm0cz60ff7fljacv75bjpy";
+    sha256 = "0m1x79q6i5fw3gr9k0dw0bbl7ym27g9vbmxiamks6yw028xqwc5a";
   };
 
-  patches = [
-    # Fix aarch64 build https://github.com/Exiv2/exiv2/pull/1271
-    (fetchpatch {
-      name = "cmake-fix-aarch64.patch";
-      url = "https://github.com/Exiv2/exiv2/commit/bbe0b70840cf28b7dd8c0b7e9bb1b741aeda2efd.patch";
-      sha256 = "13zw1mn0ag0jrz73hqjhdsh1img7jvj5yddip2k2sb5phy04rzfx";
-    })
-
-    # Use correct paths with multiple outputs
-    # https://github.com/Exiv2/exiv2/pull/1275
-    (fetchpatch {
-      url = "https://github.com/Exiv2/exiv2/commit/48f2c9dbbacc0ef84c8ebf4cb1a603327f0b8750.patch";
-      sha256 = "vjB3+Ld4c/2LT7nq6uatYwfHTh+HeU5QFPFXuNLpIPA=";
-    })
-    # https://github.com/Exiv2/exiv2/pull/1294
-    (fetchpatch {
-      url = "https://github.com/Exiv2/exiv2/commit/306c8a6fd4ddd70e76043ab255734720829a57e8.patch";
-      sha256 = "0D/omxYxBPGUu3uSErlf48dc6Ukwc2cEN9/J3e7a9eU=";
-    })
-  ];
-
   nativeBuildInputs = [
     cmake
     doxygen
@@ -55,6 +34,8 @@ stdenv.mkDerivation rec {
     libxslt
   ];
 
+  buildInputs = lib.optional stdenv.isDarwin libiconv;
+
   propagatedBuildInputs = [
     expat
     zlib
diff --git a/pkgs/os-specific/linux/evdi/default.nix b/pkgs/os-specific/linux/evdi/default.nix
index a8a0445e955..7bf25bf7caa 100644
--- a/pkgs/os-specific/linux/evdi/default.nix
+++ b/pkgs/os-specific/linux/evdi/default.nix
@@ -1,14 +1,14 @@
-{ lib, stdenv, fetchFromGitHub, fetchpatch, kernel, libdrm }:
+{ lib, stdenv, fetchFromGitHub, kernel, libdrm }:
 
 stdenv.mkDerivation rec {
   pname = "evdi";
-  version = "unstable-20210401";
+  version = "unstable-2021-07-07";
 
   src = fetchFromGitHub {
     owner = "DisplayLink";
     repo = pname;
-    rev = "b0b3d131b26df62664ca33775679eea7b70c47b1";
-    sha256 = "09apbvdc78bbqzja9z3b1wrwmqkv3k7cn3lll5gsskxjnqbhxk9y";
+    rev = "b0b2c80eb63f9b858b71afa772135f434aea192a";
+    sha256 = "sha256-io+CbZovGjEJjwtmARFH23Djt933ONoHMDoea+i6xFo=";
   };
 
   nativeBuildInputs = kernel.moduleBuildDependencies;
diff --git a/pkgs/servers/samba/4.x.nix b/pkgs/servers/samba/4.x.nix
index 3ae30699546..1139aeb4bbd 100644
--- a/pkgs/servers/samba/4.x.nix
+++ b/pkgs/servers/samba/4.x.nix
@@ -1,6 +1,5 @@
 { lib, stdenv
 , fetchurl
-, python
 , pkg-config
 , bison
 , flex
@@ -62,6 +61,7 @@ stdenv.mkDerivation rec {
   ];
 
   nativeBuildInputs = [
+    python3Packages.python
     pkg-config
     bison
     flex
@@ -78,7 +78,8 @@ stdenv.mkDerivation rec {
   ];
 
   buildInputs = [
-    python
+    python3Packages.python
+    python3Packages.wrapPython
     readline
     popt
     dbus
@@ -128,6 +129,8 @@ stdenv.mkDerivation rec {
     ++ optional (!enableAcl) "--without-acl-support"
     ++ optional (!enablePam) "--without-pam";
 
+  pythonPath = [ python3Packages.dnspython tdb ];
+
   preBuild = ''
     export MAKEFLAGS="-j $NIX_BUILD_CORES"
   '';
@@ -146,6 +149,9 @@ stdenv.mkDerivation rec {
     patchelf --shrink-rpath "\$BIN";
     EOF
     find $out -type f -name \*.so -exec $SHELL -c "$SCRIPT" \;
+
+    # Fix PYTHONPATH for some tools
+    wrapPythonPrograms
   '';
 
   passthru = {
diff --git a/pkgs/tools/text/ocrmypdf/default.nix b/pkgs/tools/text/ocrmypdf/default.nix
index 99e2bf06508..e0d8e4eb926 100644
--- a/pkgs/tools/text/ocrmypdf/default.nix
+++ b/pkgs/tools/text/ocrmypdf/default.nix
@@ -30,14 +30,13 @@ let
 in
 buildPythonApplication rec {
   pname = "ocrmypdf";
-  version = "11.7.3";
-  disabled = ! python3Packages.isPy3k;
+  version = "12.3.0";
 
   src = fetchFromGitHub {
     owner = "jbarlow83";
     repo = "OCRmyPDF";
     rev = "v${version}";
-    sha256 = "0gs2w9kl5wwrs0hx2sivq3pdvpf3lkaifblwfbz5g31yl770blji";
+    sha256 = "122yv3p0v4fbx30zgppcznwnm7svg97gv0sa103xb6zcld68ggn2";
   };
 
   nativeBuildInputs = with python3Packages; [
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 1cf5b956829..def255d9533 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -19702,7 +19702,6 @@ in
 
   samba4 = callPackage ../servers/samba/4.x.nix {
     rpcgen = netbsd.rpcgen;
-    python = python3;
   };
 
   samba = samba4;