diff --git a/install/sql/incremental/upd_0026.sql b/install/sql/incremental/upd_0026.sql
index b5787a925ee3e1c9432e51313bc6945c8987c2f5..a859ee2713c8f4d2c76136e764cbdb26944e9b47 100644
--- a/install/sql/incremental/upd_0026.sql
+++ b/install/sql/incremental/upd_0026.sql
@@ -1 +1 @@
-ALTER TABLE `shell_user` CHANGE `ssh_rsa` `ssh_rsa` TEXT CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT '';
\ No newline at end of file
+ALTER TABLE `shell_user` CHANGE `ssh_rsa` `ssh_rsa` TEXT CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL;
\ No newline at end of file
diff --git a/install/sql/incremental/upd_0042.sql b/install/sql/incremental/upd_0042.sql
index 8d1b7b4c26ca7d8c4b1ef354b07ffabfd7be9dcf..1c195b53a32a4bb57c2b8effc2df4baa88de9f2f 100644
--- a/install/sql/incremental/upd_0042.sql
+++ b/install/sql/incremental/upd_0042.sql
@@ -1,4 +1,4 @@
 
 -- increase column size
-ALTER TABLE `client` CHANGE `template_additional` `template_additional` TEXT NOT NULL DEFAULT '';
+ALTER TABLE `client` CHANGE `template_additional` `template_additional` TEXT NOT NULL;
 
diff --git a/install/sql/incremental/upd_0067.sql b/install/sql/incremental/upd_0067.sql
index 10eb88fe2a3b4ac18cb81e014675b5de77e0d381..3604460f651b6692b4c5539e9cdf6f928be8731a 100644
--- a/install/sql/incremental/upd_0067.sql
+++ b/install/sql/incremental/upd_0067.sql
@@ -1,7 +1,7 @@
 ALTER TABLE `client`
-	ADD `web_servers` blob NOT NULL DEFAULT '' AFTER `default_webserver`,
-	ADD `mail_servers` blob NOT NULL DEFAULT '' AFTER `default_mailserver`,
-	ADD `db_servers` blob NOT NULL DEFAULT '' AFTER `default_dbserver`,
-	ADD `dns_servers` blob NOT NULL DEFAULT '' AFTER `default_dnsserver`;
+	ADD `web_servers` blob NOT NULL AFTER `default_webserver`,
+	ADD `mail_servers` blob NOT NULL AFTER `default_mailserver`,
+	ADD `db_servers` blob NOT NULL AFTER `default_dbserver`,
+	ADD `dns_servers` blob NOT NULL AFTER `default_dnsserver`;
 
 UPDATE `client` SET `web_servers` = `default_webserver`, `mail_servers` = `default_mailserver`, `db_servers` = `default_dbserver`, `dns_servers` = `default_dnsserver` WHERE 1;