diff --git a/bin/hushlist-send-file b/bin/hushlist-send-file
index 6ddef90..9f38942 100755
--- a/bin/hushlist-send-file
+++ b/bin/hushlist-send-file
@@ -15,9 +15,14 @@ use JSON;
 
 my ($from,$to,$filename,$amount) = @ARGV;
 $amount ||= 0.0;
+# this is for Sprout, Sapling will not have a limit except for block size(!)
+my $max_size = 512 * 54 - 54;
 
 die "You must specify a filename!" unless $filename;
 die "File does not exist!" unless -e $filename;
+my $filesize = -s $filename;
+die "File is empty!" unless $filesize;
+die "Currently this tool only supports files which fit in one transaction, up to $max_size bytes. Patches welcome!" unless ($filesize <= $max_size);
 
 my $memo     = read_file($filename);
 my $length   = length $memo;
diff --git a/lib/Hush/Util.pm b/lib/Hush/Util.pm
index 960d952..5938ffa 100644
--- a/lib/Hush/Util.pm
+++ b/lib/Hush/Util.pm
@@ -25,6 +25,7 @@ sub is_valid_zaddr {
     #warn "zaddr=$z";
 
     # TODO: only base58 is valid
+    # TODO: support Zcash Sapling addresses
     if ($z =~ m/^zc[a-z0-9]{93}$/i) {
         return 1;
     } else {
@@ -37,8 +38,11 @@ sub is_valid_taddr {
     my ($t) = @_;
 
     # TODO: only base58 is valid
+    # HUSH/ZEC and most zec forks
     if ($t =~ m/^t1[a-z0-9]{33}$/i) {
         return 1;
+    } elsif ($t =~ m/^R[a-z0-9]{34}$/i) { # KMD and KMD asset chains
+        return 1;
     } else {
         return 0;
     }
@@ -48,6 +52,7 @@ sub is_valid_taddr {
 sub is_valid_privkey {
     my ($p) = @_;
     $p =~ s!^hushlist://!!g;
+    # TODO: support KMD + new Sapling privkeys
     if ($p =~ m/^SK[a-z0-9]{53}$/i) {
         return 1;
     } else {