# Difference in Random numbers between 1.5 & 1.6
**URL:** https://discourse.julialang.org/t/difference-in-random-numbers-between-1-5-1-6/69090
**Category:** General Usage
**Tags:** random
**Created:** [October 2, 2021, 3:53am UTC](https://discourse.julialang.org/t/difference-in-random-numbers-between-1-5-1-6/69090 "2021-10-02T03:53:53Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@bluesmoon](https://discourse.julialang.org/u/bluesmoon)
#### Post date: [October 2, 2021, 3:53am UTC](https://discourse.julialang.org/t/difference-in-random-numbers-between-1-5-1-6/69090/1 "2021-10-02T03:53:53Z")
The HISTORY.md file does not show any changes to Random number generation between v1.5 and v1.6, but I still see different numbers generated with the same seed/RNG:
Julia 1.5.4:
```julia
julia> VERSION
v"1.5.4"
julia> using Random
julia> observed=rand(MersenneTwister(1234), 0:100, 5)
5-element Array{Int64,1}:
10
37
74
12
95
```
Julia 1.6.3:
```julia
julia> VERSION
v"1.6.3"
julia> using Random
julia> observed=rand(MersenneTwister(1234), 0:100, 5)
5-element Vector{Int64}:
48
60
94
60
12
```
Could anyone help explain what’s happening?
Thank you.
---
### Author:  [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)
#### Post date: [October 2, 2021, 4:00am UTC](https://discourse.julialang.org/t/difference-in-random-numbers-between-1-5-1-6/69090/2 "2021-10-02T04:00:23Z")
The TLDR is don’t assume random numbers will be the same between versions. If you want random numbers that are the same between versions use [StableRNGs](https://juliahub.com/ui/Packages/StableRNGs/fu6AW/1.0.0).
---
### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [October 2, 2021, 6:42am UTC](https://discourse.julialang.org/t/difference-in-random-numbers-between-1-5-1-6/69090/3 "2021-10-02T06:42:48Z")
This is [documented](https://docs.julialang.org/en/v1.5/stdlib/Random/) and expected behavior.
As a heads up: julia 1.7 will switch from MersenneTwister to Xoshiro (a much faster and easier to parallelize pseudo RNG), as well as have a different RNG object per task, which will also change the stream of random numbers.
---
### Author:  [@bluesmoon](https://discourse.julialang.org/u/bluesmoon)
#### Post date: [October 2, 2021, 2:37pm UTC](https://discourse.julialang.org/t/difference-in-random-numbers-between-1-5-1-6/69090/4 "2021-10-02T14:37:52Z")
Thanks. I knew about the change in 1.7, but we’re planning a move to 1.6 since it will be the next LTS. I didn’t expect 1.6 to be different, but I understand why.
---
### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [October 2, 2021, 3:46pm UTC](https://discourse.julialang.org/t/difference-in-random-numbers-between-1-5-1-6/69090/5 "2021-10-02T15:46:40Z")
If you’re planning such a large version jump, also note that due to performance improvements and improvements to numerical accuracy, exact bitpatterns for floating point results are not guaranteed between versions.
If there was such a guarantee, almost any change to floating point algorithms would be breaking.
---
### Author:  [@bluesmoon](https://discourse.julialang.org/u/bluesmoon)
#### Post date: [October 3, 2021, 2:27am UTC](https://discourse.julialang.org/t/difference-in-random-numbers-between-1-5-1-6/69090/6 "2021-10-03T02:27:58Z")
I didn’t think 1.5.4 → 1.6.3 was a big jump, it’s just the next available version even though it is a minor version jump.
FWIW, I have over 70000 unit tests and the only one that fails after changing versions is the one that assumed `random` would be the same.