Gecko versions and application versions

The following table shows the various versions of Gecko and what versions of common applications are based on them. Note that after Gecko 2.0, both Firefox and Thunderbird versions are from then on the same as the Gecko version number, at Gecko 5.0.

Gecko version Applications based on it
Gecko 55 Firefox 55, SeaMonkey 2.52
Gecko 52 Firefox 52, SeaMonkey 2.49
Gecko 49 Firefox 49, SeaMonkey 2.46
Gecko 43 Firefox 43, SeaMonkey 2.40
Gecko 42 Firefox 42, SeaMonkey 2.39
Gecko 41 Firefox 41, SeaMonkey 2.38
Gecko 38 Firefox 38, SeaMonkey 2.35
Gecko 36 Firefox 36, SeaMonkey 2.33
Gecko 35 Firefox 35, SeaMonkey 2.32
Gecko 34 Firefox 34, SeaMonkey 2.31
Gecko 33 Firefox 33, SeaMonkey 2.30
Gecko 32 Firefox 32, SeaMonkey 2.29
Gecko 29 Firefox 29, SeaMonkey 2.26
Gecko 28 Firefox 28, SeaMonkey 2.25
Gecko 27 Firefox 27, SeaMonkey 2.24
Gecko 26 Firefox 26, SeaMonkey 2.23
Gecko 25 Firefox 25, SeaMonkey 2.22
Gecko 24 Firefox 24, Thunderbird 24, SeaMonkey 2.21
Gecko 23 Firefox 23, SeaMonkey 2.20
Gecko 22 Firefox 22, SeaMonkey 2.19
Gecko 21 Firefox 21, SeaMonkey 2.18
Gecko 20 Firefox 20, SeaMonkey 2.17
Gecko 19 Firefox 19, SeaMonkey 2.16
Gecko 18 Firefox 18, Firefox OS 1.0, SeaMonkey 2.15
Gecko 17 Firefox 17, Thunderbird 17, SeaMonkey 2.14
Gecko 16 Firefox 16, Thunderbird 16, SeaMonkey 2.13
Gecko 15 Firefox 15, Thunderbird 15, SeaMonkey 2.12
Gecko 14 Firefox 14, Thunderbird 14, SeaMonkey 2.11
Gecko 13 Firefox 13, Thunderbird 13, SeaMonkey 2.10
Gecko 12 Firefox 12, Thunderbird 12, SeaMonkey 2.9
Gecko 11 Firefox 11, Thunderbird 11, SeaMonkey 2.8
Gecko 10 Firefox 10, Thunderbird 10, SeaMonkey 2.7
Gecko 9 Firefox 9, Thunderbird 9, SeaMonkey 2.6
Gecko 8 Firefox 8, Thunderbird 8, SeaMonkey 2.5
Gecko 7 Firefox 7, Thunderbird 7, SeaMonkey 2.4
Gecko 6 Firefox 6, Thunderbird 6, SeaMonkey 2.3
Gecko 5 Firefox 5, Thunderbird 5, SeaMonkey 2.2
Gecko 2 Firefox 4, Thunderbird 3.3, SeaMonkey 2.1
Gecko 1.9.2 Firefox 3.6, Thunderbird 3.1
Gecko 1.9.1 Firefox 3.5, Thunderbird 3, SeaMonkey 2.0
Gecko 1.9 Firefox 3
Gecko 1.8.1 Firefox 2, Thunderbird 2, SeaMonkey 1.1
Gecko 1.8 Firefox 1.5, Thunderbird 1.5, SeaMonkey 1.0
Gecko 1.7 Firefox 1.0, Thunderbird 1.0, Nvu 1.0, Mozilla Suite 1.7
older versions of Gecko match the Mozilla Suite versions