I cannot understand.
I tested again migration from V6.1.0 to V6.1.2, with postgresql database, and all worked like a charm

2017-03-27 20:43:38.387 ===== TRACE ===== =====================================
2017-03-27 20:43:38.388 ===== TRACE ===== 
2017-03-27 20:43:38.389 ===== TRACE ===== DataBase actual Version = V6.1.0
2017-03-27 20:43:38.389 ===== TRACE ===== ProjeQtOr actual Version = V6.1.2
2017-03-27 20:43:38.390 ===== TRACE ===== 
2017-03-27 20:43:38.391 ===== TRACE ===== =====================================
2017-03-27 20:43:38.392 ===== TRACE ===== 
2017-03-27 20:43:38.392 ===== TRACE ===== VERSION V6.1.1
2017-03-27 20:43:38.393 ===== TRACE ===== 
2017-03-27 20:43:38.403 ===== TRACE =====  1 lines updated into table "menu".
2017-03-27 20:43:38.405 ===== TRACE =====  2 lines updated into table "menu".
2017-03-27 20:43:38.406 ===== TRACE ===== 
2017-03-27 20:43:38.406 ===== TRACE ===== DATABASE UPDATED
2017-03-27 20:43:38.407 ===== TRACE =====  WITH NO ERROR
2017-03-27 20:43:38.407 ===== TRACE ===== 
2017-03-27 20:43:38.533 ===== TRACE ===== =====================================
2017-03-27 20:43:38.533 ===== TRACE ===== 
2017-03-27 20:43:38.534 ===== TRACE ===== DATABASE UPDATE COMPLETED TO VERSION V6.1.2
2017-03-27 20:43:38.534 ===== TRACE ===== 
2017-03-27 20:43:38.535 ===== TRACE ===== =====================================
2017-03-27 20:43:38.535 ===== TRACE ===== 

Hello,
I check with a new server empty install (from scrach). With php 7.1.
On the first connexion with admin user for create new database i have same error.
After investigation the problem seems becom from PDO module.
In ../model/persistence/Sql.php at line 144 with error " cause = SQLSTATE[55000]: Object not in prerequisite state: 7 ERROR: lastval is not yet defined in this session"

Do you think this page: https://fuelphp.com/forums/discussion/14057/uncaught-exception-pdoexception-sqlstate55000 is applicable ?

I have solve the problem with a upddate of PDO module find here: https://github.com/kipkaev55/fuel-pqlib
The problem are present for php 7.1 (last version)

Hi,

We already pointed out that ProjeQtOr is not compatible with PHP 7.1
This version of PHP includes serious regressions in management of numeric values that leads to incompatiblity with many applications (including symfony framework)

thanks, it is just a test but in production i use php7.0 correct ?

Yes.
Projeqtor is compatible with PHP V7.0