Index: subversion/libsvn_fs_fs/fs_fs.c
===================================================================
--- subversion/libsvn_fs_fs/fs_fs.c	(revision 1804416)
+++ subversion/libsvn_fs_fs/fs_fs.c	(working copy)
@@ -861,7 +861,7 @@ read_config(fs_fs_data_t *ffd,
     }
 
   /* Initialize compression settings in ffd. */
-  if (ffd->format >= SVN_FS_FS__MIN_SVNDIFF2_FORMAT)
+  if (ffd->format >= SVN_FS_FS__MIN_DELTIFICATION_FORMAT)
     {
       const char *compression_val;
       const char *compression_level_val;
@@ -872,12 +872,23 @@ read_config(fs_fs_data_t *ffd,
       svn_config_get(config, &compression_level_val,
                      CONFIG_SECTION_DELTIFICATION,
                      CONFIG_OPTION_COMPRESSION_LEVEL, NULL);
-      if (compression_val)
+      if (compression_val && compression_level_val)
         {
-          /* 'compression' option overrides deprecated 'compression-level'. */
+          return svn_error_create(SVN_ERR_BAD_CONFIG_VALUE, NULL,
+                                  _("The 'compression' and 'compression-level' "
+                                    "config options are mutually exclusive"));
+        }
+      else if (compression_val)
+        {
           SVN_ERR(parse_compression_option(&ffd->delta_compression_type,
                                            &ffd->delta_compression_level,
                                            compression_val));
+          if (ffd->delta_compression_type == compression_type_lz4 &&
+              ffd->format < SVN_FS_FS__MIN_SVNDIFF2_FORMAT)
+            {
+              return svn_error_create(SVN_ERR_UNSUPPORTED_FEATURE, NULL,
+                                      _("Unsupported compression type 'lz4'"));
+            }
         }
       else if (compression_level_val)
         {
@@ -897,19 +908,6 @@ read_config(fs_fs_data_t *ffd,
           ffd->delta_compression_level = SVN_DELTA_COMPRESSION_LEVEL_DEFAULT;
         }
     }
-  else if (ffd->format >= SVN_FS_FS__MIN_DELTIFICATION_FORMAT)
-    {
-      apr_int64_t compression_level;
-
-      SVN_ERR(svn_config_get_int64(config, &compression_level,
-                                   CONFIG_SECTION_DELTIFICATION,
-                                   CONFIG_OPTION_COMPRESSION_LEVEL,
-                                   SVN_DELTA_COMPRESSION_LEVEL_DEFAULT));
-      ffd->delta_compression_type = compression_type_zlib;
-      ffd->delta_compression_level =
-        (int)MIN(MAX(SVN_DELTA_COMPRESSION_LEVEL_NONE, compression_level),
-                 SVN_DELTA_COMPRESSION_LEVEL_MAX);
-    }
   else if (ffd->format >= SVN_FS_FS__MIN_SVNDIFF1_FORMAT)
     {
       ffd->delta_compression_type = compression_type_zlib;
@@ -1062,6 +1060,7 @@ write_config(svn_fs_t *fs,
 "### significantly speed up commits as well as reading the data."            NL
 "### The syntax of this option is:"                                          NL
 "###   " CONFIG_OPTION_COMPRESSION " = none | lz4 | zlib | zlib-1 ... zlib-9" NL
+"### Versions prior to Subversion 1.10 will ignore this option."             NL
 "### The default value is 'zlib', which is currently equivalent to 'zlib-5'." NL
 "# " CONFIG_OPTION_COMPRESSION " = zlib"                                     NL
 "###"                                                                        NL
Index: subversion/tests/cmdline/svntest/main.py
===================================================================
--- subversion/tests/cmdline/svntest/main.py	(revision 1804416)
+++ subversion/tests/cmdline/svntest/main.py	(working copy)
@@ -2202,10 +2202,6 @@ def parse_options(arglist=sys.argv[1:], usage=None
   if options.fsfs_packing and not options.fsfs_sharding:
     parser.error("--fsfs-packing requires --fsfs-sharding")
 
-  if options.fsfs_compression is not None and \
-     options.server_minor_version < 10:
-    parser.error("--fsfs-compression requires --server-minor-version=10")
-
   if options.server_minor_version not in range(3, SVN_VER_MINOR+1):
     parser.error("test harness only supports server minor versions 3-%d"
                  % SVN_VER_MINOR)