// validate checksum
   uint8 addressHash[32];
   sha256_ctx s256c;
   sha256_init(&s256c);
   sha256_update(&s256c, walletAddressRaw, walletAddressRawLength-4);
   sha256_final(&s256c, addressHash);
   sha256_init(&s256c);
   sha256_update(&s256c, addressHash, 32);
   sha256_final(&s256c, addressHash);
   if( *(uint32*)(walletAddressRaw+21) != *(uint32*)addressHash )
   {
      printf("xptClient_addDeveloperFeeEntry(): Invalid checksum\n");
      return;
   }
// address ok, check if there is still free space in the list
   if( xptClient->developerFeeCount >= XPT_DEVELOPER_FEE_MAX_ENTRIES )
   {
      printf("xptClient_addDeveloperFeeEntry(): Maximum number of developer fee entries exceeded\n");
      return;
   }


This is causing the problem  I imagine. Can anyone modify the client assuming they are following the same code sha checks. I wouldn't know where to start