@machour I am sorry it seems that we need to revert #705. The existed ip.txt makes RCTBundleURLProvider.m:guessPackagerHost returns empty string as the packager host.
And adding ip.txt to .gitignore can not prevent git from reminding about local changes. Maybe because it is already recorded by git.
Don't know why the following error is not found previously. Not sure whether related to the upgrade of RN(#757) or not.

@machour I am sorry it seems that we need to revert #705. The existed
ip.txtmakesRCTBundleURLProvider.m:guessPackagerHostreturns empty string as the packager host.And adding
ip.txtto.gitignorecan not prevent git from reminding about local changes. Maybe because it is already recorded by git.Don't know why the following error is not found previously. Not sure whether related to the upgrade of RN(#757) or not.