I have been using autoconfig (thunderbird.cfg) for many years. After switching from 52.9.1 to 60.9.0, my script began to behave strangely. Among other things, it changes the contents of some preferences using the pref() function. In particular, ldap_2.servers.public.uri. Earlier, when calling pref ("ldap_2.servers.public.uri", "new value"), the contents of this line simply changed, but now a new section is created containing the old values ​​"ldap_2.servers.public.uri", "ldap_2.servers.public.filename" and "ldap_2.servers.public.description" under the names "ldap_2.servers.public_1.uri", "ldap_2.servers.public_1.filename" and "ldap_2.servers.public_1.description". On the next change, they become "public_2", and "public" again becomes "public_1". As a result, instead of changing the way I access the server depending on my IP address, I get a new address book every time thunderbird starts. How to return the old behavior of the pref() function or change the value of named preference in another way? And by the way, why now getPref("extensions.enabledAddons") always returns NULL? I could not find answers on Mozilla sites ;(