DBMail migration 2 -> 3 : datefield issue

Hi,

I have migrate from

- DBMail version 2.2.17
- mysql  Ver 14.14 Distrib 5.5.21, for Linux (x86_64) using readline 5.1

to

- DBMail version 3.0.2
- mysql  Ver 14.14 Distrib 5.1.73, for redhat-linux-gnu (x86_64) using 
readline 5.1

with imapsync.

Here is the datefield comparing for some selected messages :

2.2.17:

+---------------------+------------------------------------+--------+----------------------------------+----------------+----------+
| datefield           | LEFT(sb.subjectfield,24) | status | 
unique_id                        | physmessage_id | rfcsize  |
+---------------------+------------------------------------+--------+----------------------------------+----------------+----------+
| 1901-12-13 20:55:13 | ..................... |      0 | 
b6124d0f7b44d221663c53e620b2493e |          63086 |      727 |
| 2000-02-28 09:19:21 | ..................... |      1 | 
6e37728b36205d9f290796ee856632e5 |          23849 | 76574 |
| 2000-02-28 09:32:28 |..................... |      1 | 
da25fd22e07bb7c0bf6054cafc1bfb87 |          23848 | 2945 |
| 2000-02-29 16:21:11 | ..................... |      1 | 
34c93a33897128ea93d8e09aae981e69 |          23847 | 373734 |
| 2000-03-04 21:39:27 | ..................... |      1 | 
ee861b69449a68514fa4562702d7e15e |          23846 | 1646 |

3.0.2:

+---------------------+--------------------------+--------+----------------------------------+----------------+----------+
| datefield           | LEFT(sb.subjectfield,24) | status 
|unique_id                        | physmessage_id | rfcsize  |
+---------------------+--------------------------+--------+----------------------------------+----------------+----------+
| 1900-07-01 00:00:00 | .....................    |      1 | 
9b301c7a2a112a7818cf3332a87910ee |           3826 |      727 |
| 2000-02-28 00:00:00 | ..................... |      1 | 
6358c66b9155bb0b5cc05e293e17822e |          25124 | 76574 |
| 2000-02-28 00:00:00 | ..................... |      1 | 
a4fed6f928b4250c712d95107776172c |          25123 |     2945 |
| 2000-02-29 00:00:00 | ..................... |      1 | 
f6281d5d5557e9a151879b78853850d0 |          25122 | 373734 |
| 2000-03-04 00:00:00 | ......................   |      1 | 
7cecd714baec8b8f2c154231ae6f57b9 |          25121 |     1646 |

Any suggestion ?

Thanks in advance.

Pascal