Update:

• Now uses "great-grandson"/"great-granddaughter" and appropriate pronouns based on the baby's gender. Thanks, DiLight!
• Reuploaded gender-neutral version as greatgrandchildmemory-genderneutral by request.
• Now with Polish localization for the gendered version. Thanks xaosem!
• Now with Russian localization for the gendered version. Thanks Anitne!
• Now with Brazilian Portuguese localization for the gendered version. Thanks Netero!
• Now with Spanish localization for the gendered version. Thanks tonivalencia!
• Now with Dutch localization for both versions. Thanks __TuuT__!

I guess EA never imagined sims would live to see their great-grandchildren (even though they gave us resurrection and vampires and elixir of life!). With this hack, sims will get a custom memory when they have great-grandchildren, similar to the one they get when they have grandchildren. I made this to go along with my extended family hack, which will also allow family interactions between great-grandparents and great-grandchildren, but this actually doesn't require it.

Game Compatibility

This should be compatible with all game configurations.

Hack Compatibility

This hack consists of a custom memory object and a modification to BHAV 0x100B in group 0x7F1D0F49, which in the original game locates a new baby's grandparents and gives them the "Met New Grandchild" memory. It should only conflict with other hacks that modify this function for whatever reason.

Note about uninstalling the hack

Since this adds a new custom memory, before uninstalling it you should open your neighborhood in SimPE and delete all of the "Met New Great-Grandchild" memories from your sims, and then open the game and delete all gossip using the lot debugger.

Acknowledgements

Thanks to MTS user DiLight for providing a helpful tutorial to get me started, and to various other users who gave me ideas about the text to use for the memory.