Please test pari-2.13.1 prerelease 1

Dear PARI developers,

We have made available a prerelease of PARI 2.13.1 (stable).

Please test there are no regressions.

The expected release date is set to the 25/01/2021.

Please test the prerelease tarball:
<https://pari.math.u-bordeaux.fr/pub/pari/snapshots/pari-2.13.1-pre1.tar.gz>

The digital signature is 
<https://pari.math.u-bordeaux.fr/pub/pari/snapshots/pari-2.13.1-pre1.tar.gz.asc>

Please test the 64bit windows installer:
<https://pari.math.u-bordeaux.fr/pub/pari/windows/snapshots/Pari64-2.13.1-pre1.exe>

I have also built the 32bit Windows installer:
<https://pari.math.u-bordeaux.fr/pub/pari/windows/snapshots/Pari32-2.13.1-pre1.exe>

and the following standalone Windows binaries:

32bit 
<https://pari.math.u-bordeaux.fr/pub/pari/windows/snapshots/gp32-2.13.1-pre1.exe>
<https://pari.math.u-bordeaux.fr/pub/pari/windows/snapshots/gp32-readline-2.13.1-pre1.exe>

64bit
<https://pari.math.u-bordeaux.fr/pub/pari/windows/snapshots/gp64-2.13.1-pre1.exe>
<https://pari.math.u-bordeaux.fr/pub/pari/windows/snapshots/gp64-readline-2.13.1-pre1.exe>

64bit, multithreaded
<https://pari.math.u-bordeaux.fr/pub/pari/windows/snapshots/gppthread64-2.13.1-pre1.exe>
<https://pari.math.u-bordeaux.fr/pub/pari/windows/snapshots/gppthread64-readline-2.13.1-pre1.exe>

and the following MacOS DMG:

<https://pari.math.u-bordeaux.fr/pub/pari/mac/snapshots/PariGP-2.13.1-pre1.dmg>
<https://pari.math.u-bordeaux.fr/pub/pari/mac/snapshots/PariGP-2.13.1-pre1-pthread.dmg>
<https://pari.math.u-bordeaux.fr/pub/pari/mac/snapshots/PariGP-full-2.13.1-pre1.dmg>
<https://pari.math.u-bordeaux.fr/pub/pari/mac/snapshots/PariGP-full-2.13.1-pre1-pthread.dmg>

and the following MacOS stand-alone binaries:
<https://pari.math.u-bordeaux.fr/pub/pari/mac/snapshots/gp-2.13.1-pre1-osx>
<https://pari.math.u-bordeaux.fr/pub/pari/mac/snapshots/gp-2.13.1-pre1-pthread-osx>

The changelog:

Bug numbers refer to the BTS at http://pari.math.u-bordeaux.fr/Bugs/

  Fixed
     1- GC error in idealinv [#2258]                                      [F2]
     2- qfminim inefficiency (initial bound from non-LLL-reduced matrix)  [F3]
     3- mfshimura in weight 3/2 => oo loop                                [F4]
     4- matsolve([1,1,1/2; 1,0,1/2; 2,1,0], [-1;1;-1]) -> SEGV [#2261]    [F6]
     5- qfminim(Mat(1),,,2) -> precision error [#2262]                    [F7]
     6- subst(p, v, t_SER) very slow if p contains many variables [#2264] [F8]
     7- mfsymboleval for trivial path returned 0 instead of a vector of 0s
        when f has multiple embeddings [#2260]                            [F9]
     8- 2^(1 + O(3^4)) -> type error                                      [F10]
     9- Zn_quad_roots(8,0,-1) to compute roots of x^2-1 mod 8 -> [4,[1,3]]
        (1 or 3 mod 4) instead of the expected [2,[1]] (1 mod 2) [#2265]  [F11]
    10- tan(1+10^20*I) -> overflow (same for cotan and psi)               [F12]
BA  11- Mod(2,3)^1000000000000000000001 -> Mod(-1,3) [#2266]              [F13]
    12- subst(O(y) + x, x, (1 - y + O(y^2))*x + O(x^2)) -> SEGV [#2267]   [F14]
    13- (Mod(0,3) + x) + O(x^2) -> x + O(x^2)  [now Mod(1,3)*x + O(x^2)]  [F15]
    14- precision too low for units in mfgaloisprojrep                    [F16]
    15- missing GC at the end of RgXn_inv                                 [F17]
    16- (-1)^(1/3) -> -1 instead of exp(log(-1)/3)                        [F18]
    17- mfeisenstein(k, trivial characters mod N > 1) was incorrect       [F19]
BA  18- missing GC in qfsolve                                             [F20]

On behalf of the PARI group,
Bill and Karim