During upgrade is necessary to adjust "connections" parameter in /etc/named.conf.

Minimal value depends on configuration:

• without persistent search: "connections 2"
• with persistent search enabled: "connections 3"

Another option is to simply delete "connections" parameter, if it's <= 2 (and let plugin use correct default value).

Required parameters without persistent search:

dynamic-db "ipa" {
        arg "psearch no";
        arg "connections 2";
};

Required parameters with persistent search:

dynamic-db "ipa" {
        arg "psearch yes";
        arg "connections 3";
};