Sorin Cosoveanu has provided me with some documentation about changes in Equatorial Guinea. A new city, Oyala, has been built as a future capital. Its name has been changed to Djibloho. And now it has been split from Añisok district as a new district, and simultaneously made a new province, split from Wele-Nzas province, both named Djibloho. Source [4] says that Djibloho province has two urban districts: Oyala and Mbere. I have changed the HASC code for Wele-Nzas province, and for all its districts correspondingly.

Equatorial Guinea is divided into eight provinces, which are further divided into thirty-one districts. In 1994, there were only seventeen districts. They can be located on this page , apparently an official government website, with links to seven province pages with maps showing the division of the provinces into districts. This PDF document  from Marathon Petroleum has a map of the whole country showing the same division into districts (page 12). I haven't been able to find any maps of the thirty districts yet.

Change history:

1. ~1997: Thirteen new districts were apparently created between 1994 and 2001.
2. 2015-08-03: Djibloho district split from Añisok (former HASC code GQ.WN.AS).

Other names of subdivisions:

1. Aconibe: Akonibe (variant)
2. Acurenam: Akurenam (variant)
3. Annobón: San Antonio Palea (variant)
4. Cogo: Kogo (variant)
5. Micomeseng: Micomiseng (variant)
6. Mongomeyen: Mengomeyén (variant)

Population history: