Trouble with Support library version of 25 and 26 !

Hi guys!
If anybody had faced any issues like i am doing kindly let me know how am i to proceed.

What i did:
We have numerous SDKs involved with the Unity mobile game we are making. SDKs like FIrebase,Facebook,Unity Notification by Gasper etc.. This game is targeted for Android and iOS platforms. The problem is, it is working well with the iOS but not with the Android.

The Issue:
1)The Unity Notification services plugin we are using for android requires Support library 26 but Facebook requires the Support library 25. So eventually i cannot have both of them in the project because it leads to a duplication error.
2)If i delete the support library 26 then Notification will not work, If I delete support library 25 Facebook ceases to work. I don't know a possible fix for this issue. Is there a way where i could force support libraries of unity to be 26 instead of 25 be any means. Or am i doing it wrong in any way ? Any help would be appreciated and i am open to all suggestions. Thanks.