qB 4.4.0 introduces the concept of BT v2 protocol, which can be selected when making seeds

1. v1 mode (existing mode)
2. v1 mode + file alignment
3. Mixed mode (qB 4.4.0 default)
4. v2 mode

Among them, qB 4.4.0 supports all
qB < 4.4.0 and most clients support 1/2/3
uT 1.x/2.x supports 1, poor support for 2/3, there are certain compatibility issues

Therefore, everyone uses qB 4.4.0 to select v1 when making torrents, and do not upload v2 and mixed mode torrents