diff --git a/configure.ac b/configure.ac
index a14792f6..a0eb4501 100644
--- a/configure.ac
+++ b/configure.ac
@@ -265,26 +265,27 @@ AC_ARG_ENABLE(sudo,
               [SUDO_BIN="sudo"], [SUDO_BIN=""])
 AC_SUBST([SUDO_BIN])
 
-# Do we enable building peer to peer support using libostree’s experimental (non-stable) API?
-# If so, OSTREE_ENABLE_EXPERIMENTAL_API needs to be #defined before ostree.h is
-# included.
-AC_ARG_ENABLE([p2p],
-  [AS_HELP_STRING([--enable-p2p],
-                  [Enable unstable peer to peer support [default=no]])],,
-  [enable_p2p=no])
-AS_IF([test x$enable_p2p = xyes],[
-  PKG_CHECK_MODULES(OSTREE, [ostree-1 >= $OSTREE_P2P_REQS])
+# Decide whether to build with peer to peer support. This requires API in
+# libostree which before 2018.6 was experimental.
+enable_p2p=no
+PKG_CHECK_MODULES(OSTREE_P2P_REQ, [ostree-1 >= $OSTREE_P2P_REQS ostree-1 < 2018.6],[
 
   ostree_features=$($PKG_CONFIG --variable=features ostree-1)
   AS_CASE(["$ostree_features"],
           [*experimental*],[have_ostree_experimental=yes])
 
-  AS_IF([test "x$have_ostree_experimental" != "xyes"],
-        [AC_MSG_ERROR([Experimental API not found in ostree-1, which is needed for --enable-p2p. OSTree must be compiled with --enable-experimental-api.])])
-
-  AC_DEFINE([OSTREE_ENABLE_EXPERIMENTAL_API],[1],[Define if libostree experimental API should be enabled])
+  AS_IF([test "x$have_ostree_experimental" != "xyes"],[
+      AC_MSG_WARN([Experimental API not found in ostree-1, so flatpak will be compiled without P2P support. OSTree < 2018.6 must be compiled with --enable-experimental-api.])
+    ],[
+      enable_p2p=yes
+      AC_DEFINE([OSTREE_ENABLE_EXPERIMENTAL_API],[1],[Define if libostree experimental API should be enabled])
+      AC_DEFINE([FLATPAK_ENABLE_P2P],[1],[Define if peer to peer support should be enabled])
+    ])
+], :)
+PKG_CHECK_MODULES(OSTREE_2018_6, [ostree-1 >= 2018.6],[
+  enable_p2p=yes
   AC_DEFINE([FLATPAK_ENABLE_P2P],[1],[Define if peer to peer support should be enabled])
-])
+], :)
 AM_CONDITIONAL([ENABLE_P2P],[test x$enable_p2p = xyes])
 
 AC_ARG_WITH(system-install-dir,