Hunk #1/2 - Default memory limit is too low, various tests fail with
16MB. 32MB still has a failure in t/240abort.t but most things work
ok and 240abort.t represents an unusual situation. (It can be made
to work with 64MB in perl 5.28 - earlier perl needs even more).

Hunk #3 - Typo found by newer perl's "Unescaped left brace in regex"
deprecation warning.

Index: lib/Net/FTPServer.pm
--- lib/Net/FTPServer.pm.orig
+++ lib/Net/FTPServer.pm
@@ -358,7 +358,7 @@ process and are important in avoiding denial of servic
 attacks against the FTP server.
 
  Resource         Default   Unit
- limit memory       16384   KBytes  Amount of memory per child
+ limit memory       32768   KBytes  Amount of memory per child
  limit nr processes    10   (none)  Number of processes
  limit nr files        20   (none)  Number of open files
 
@@ -367,7 +367,7 @@ limit to C<-1>.
 
 Example:
 
- limit memory:       32768
+ limit memory:       65536
  limit nr processes:    20
  limit nr files:        40
 
@@ -2680,7 +2680,7 @@ sub run
     # Perform normal per-process limits.
     if ($r == 0)
       {
-	my $limit = 1024 * ($self->config ("limit memory") || 16384);
+	my $limit = 1024 * ($self->config ("limit memory") || 32768);
 	$self->_set_rlimit ("RLIMIT_DATA", $limit) if $limit >= 0;
 
 	$limit = $self->config ("limit nr processes") || 10;
@@ -6688,7 +6688,7 @@ sub _LANG_command
     # (b) there are all sorts of possible libc exploits available if
     # the user is allowed to set this to arbitrary values.
     unless (length ($rest) <= 8 &&
-	    $rest =~ /^[A-Z]{1,8}(-[A-Z]{1-8})*$/i)
+	    $rest =~ /^[A-Z]{1,8}(-[A-Z]{1,8})*$/i)
       {
 	$self->reply (504, "Incorrect language.");
 	return;