Possible to transfer WhatsApp history from Android to iOS?
Quoting Quora user Julio Cesar Sanchez Hernandez:


  The only free way I’ve found is using watoi:
  
  It requires a mac with Xcode and iTunes, and the unencrypted
  msgstore.db with the Whatsapp conversations from Android (you can get
  it using WhatsApp Key/DB Extractor)
  
  Won’t give much more details as the watoi project link has a README
  with the instructions and are easy to follow


Watoi has two limitations though, per its github page:


Media files and shared locations are not imported (got placeholders
instead)
Messages from contacts that changed ids (phone numbers) are
not linked